diff --git a/OpenRA.Game/ExternalMods.cs b/OpenRA.Game/ExternalMods.cs
index 3decd6b20c..40dc1c30c4 100644
--- a/OpenRA.Game/ExternalMods.cs
+++ b/OpenRA.Game/ExternalMods.cs
@@ -94,17 +94,17 @@ namespace OpenRA
 
 			if (sheetBuilder != null)
 			{
-				var iconNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon");
+				var iconNode = yaml.NodeWithKeyOrDefault("Icon");
 				if (iconNode != null && !string.IsNullOrEmpty(iconNode.Value.Value))
 					using (var stream = new MemoryStream(Convert.FromBase64String(iconNode.Value.Value)))
 						mod.Icon = sheetBuilder.Add(new Png(stream));
 
-				var icon2xNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon2x");
+				var icon2xNode = yaml.NodeWithKeyOrDefault("Icon2x");
 				if (icon2xNode != null && !string.IsNullOrEmpty(icon2xNode.Value.Value))
 					using (var stream = new MemoryStream(Convert.FromBase64String(icon2xNode.Value.Value)))
 						mod.Icon2x = sheetBuilder.Add(new Png(stream), 1f / 2);
 
-				var icon3xNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon3x");
+				var icon3xNode = yaml.NodeWithKeyOrDefault("Icon3x");
 				if (icon3xNode != null && !string.IsNullOrEmpty(icon3xNode.Value.Value))
 					using (var stream = new MemoryStream(Convert.FromBase64String(icon3xNode.Value.Value)))
 						mod.Icon3x = sheetBuilder.Add(new Png(stream), 1f / 3);
diff --git a/OpenRA.Game/GameRules/SoundInfo.cs b/OpenRA.Game/GameRules/SoundInfo.cs
index b42fd281f2..e2711ccf45 100644
--- a/OpenRA.Game/GameRules/SoundInfo.cs
+++ b/OpenRA.Game/GameRules/SoundInfo.cs
@@ -40,16 +40,16 @@ namespace OpenRA.GameRules
 		static Dictionary<string, SoundPool> ParseSoundPool(MiniYaml y, string key)
 		{
 			var ret = new Dictionary<string, SoundPool>();
-			var classifiction = y.Nodes.First(x => x.Key == key);
+			var classifiction = y.NodeWithKey(key);
 			foreach (var t in classifiction.Value.Nodes)
 			{
 				var volumeModifier = 1f;
-				var volumeModifierNode = t.Value.Nodes.FirstOrDefault(x => x.Key == nameof(SoundPool.VolumeModifier));
+				var volumeModifierNode = t.Value.NodeWithKeyOrDefault(nameof(SoundPool.VolumeModifier));
 				if (volumeModifierNode != null)
 					volumeModifier = FieldLoader.GetValue<float>(volumeModifierNode.Key, volumeModifierNode.Value.Value);
 
 				var interruptType = SoundPool.DefaultInterruptType;
-				var interruptTypeNode = t.Value.Nodes.FirstOrDefault(x => x.Key == nameof(SoundPool.InterruptType));
+				var interruptTypeNode = t.Value.NodeWithKeyOrDefault(nameof(SoundPool.InterruptType));
 				if (interruptTypeNode != null)
 					interruptType = FieldLoader.GetValue<SoundPool.InterruptType>(interruptTypeNode.Key, interruptTypeNode.Value.Value);
 
diff --git a/OpenRA.Game/GameRules/WeaponInfo.cs b/OpenRA.Game/GameRules/WeaponInfo.cs
index b4b76807dc..bac06ff470 100644
--- a/OpenRA.Game/GameRules/WeaponInfo.cs
+++ b/OpenRA.Game/GameRules/WeaponInfo.cs
@@ -145,7 +145,8 @@ namespace OpenRA.GameRules
 
 		static object LoadProjectile(MiniYaml yaml)
 		{
-			if (!yaml.ToDictionary().TryGetValue("Projectile", out var proj))
+			var proj = yaml.NodeWithKeyOrDefault("Projectile")?.Value;
+			if (proj == null)
 				return null;
 
 			var ret = Game.CreateObject<IProjectileInfo>(proj.Value + "Info");
diff --git a/OpenRA.Game/GameSpeed.cs b/OpenRA.Game/GameSpeed.cs
index 17233e4a52..ccb93d6c5a 100644
--- a/OpenRA.Game/GameSpeed.cs
+++ b/OpenRA.Game/GameSpeed.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Linq;
 
 namespace OpenRA
 {
@@ -38,7 +37,7 @@ namespace OpenRA
 		static object LoadSpeeds(MiniYaml y)
 		{
 			var ret = new Dictionary<string, GameSpeed>();
-			var speedsNode = y.Nodes.FirstOrDefault(n => n.Key == "Speeds");
+			var speedsNode = y.NodeWithKeyOrDefault("Speeds");
 			if (speedsNode == null)
 				throw new YamlException("Error parsing GameSpeeds: Missing Speeds node!");
 
diff --git a/OpenRA.Game/Graphics/CursorProvider.cs b/OpenRA.Game/Graphics/CursorProvider.cs
index 04c623885e..85919dbe7d 100644
--- a/OpenRA.Game/Graphics/CursorProvider.cs
+++ b/OpenRA.Game/Graphics/CursorProvider.cs
@@ -27,7 +27,7 @@ namespace OpenRA.Graphics
 			var sequenceYaml = MiniYaml.Merge(modData.Manifest.Cursors.Select(
 				s => MiniYaml.FromStream(fileSystem.Open(s), s)));
 
-			var nodesDict = new MiniYaml(null, sequenceYaml).ToDictionary();
+			var cursorsYaml = new MiniYaml(null, sequenceYaml).NodeWithKey("Cursors").Value;
 
 			// Overwrite previous definitions if there are duplicates
 			var pals = new Dictionary<string, IProvidesCursorPaletteInfo>();
@@ -35,14 +35,14 @@ namespace OpenRA.Graphics
 				if (p.Palette != null)
 					pals[p.Palette] = p;
 
-			Palettes = nodesDict["Cursors"].Nodes.Select(n => n.Value.Value)
+			Palettes = cursorsYaml.Nodes.Select(n => n.Value.Value)
 				.Where(p => p != null)
 				.Distinct()
 				.ToDictionary(p => p, p => pals[p].ReadPalette(modData.DefaultFileSystem));
 
 			var frameCache = new FrameCache(fileSystem, modData.SpriteLoaders);
 			var cursors = new Dictionary<string, CursorSequence>();
-			foreach (var s in nodesDict["Cursors"].Nodes)
+			foreach (var s in cursorsYaml.Nodes)
 				foreach (var sequence in s.Value.Nodes)
 					cursors.Add(sequence.Key, new CursorSequence(frameCache, sequence.Key, s.Key, s.Value.Value, sequence.Value));
 
diff --git a/OpenRA.Game/HotkeyDefinition.cs b/OpenRA.Game/HotkeyDefinition.cs
index 84eef05295..ad4a09a85a 100644
--- a/OpenRA.Game/HotkeyDefinition.cs
+++ b/OpenRA.Game/HotkeyDefinition.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Linq;
 
 namespace OpenRA
 {
@@ -31,29 +30,26 @@ namespace OpenRA
 			if (!string.IsNullOrEmpty(node.Value))
 				Default = FieldLoader.GetValue<Hotkey>("value", node.Value);
 
-			var descriptionNode = node.Nodes.FirstOrDefault(n => n.Key == "Description");
-			if (descriptionNode != null)
-				Description = descriptionNode.Value.Value;
+			var nodeDict = node.ToDictionary();
 
-			var typesNode = node.Nodes.FirstOrDefault(n => n.Key == "Types");
-			if (typesNode != null)
-				Types = FieldLoader.GetValue<HashSet<string>>("Types", typesNode.Value.Value);
+			if (nodeDict.TryGetValue("Description", out var descriptionYaml))
+				Description = descriptionYaml.Value;
 
-			var contextsNode = node.Nodes.FirstOrDefault(n => n.Key == "Contexts");
-			if (contextsNode != null)
-				Contexts = FieldLoader.GetValue<HashSet<string>>("Contexts", contextsNode.Value.Value);
+			if (nodeDict.TryGetValue("Types", out var typesYaml))
+				Types = FieldLoader.GetValue<HashSet<string>>("Types", typesYaml.Value);
 
-			var platformNode = node.Nodes.FirstOrDefault(n => n.Key == "Platform");
-			if (platformNode != null)
+			if (nodeDict.TryGetValue("Contexts", out var contextYaml))
+				Contexts = FieldLoader.GetValue<HashSet<string>>("Contexts", contextYaml.Value);
+
+			if (nodeDict.TryGetValue("Platform", out var platformYaml))
 			{
-				var platformOverride = platformNode.Value.Nodes.FirstOrDefault(n => n.Key == Platform.CurrentPlatform.ToString());
+				var platformOverride = platformYaml.NodeWithKeyOrDefault(Platform.CurrentPlatform.ToString());
 				if (platformOverride != null)
 					Default = FieldLoader.GetValue<Hotkey>("value", platformOverride.Value.Value);
 			}
 
-			var readonlyNode = node.Nodes.FirstOrDefault(n => n.Key == "Readonly");
-			if (readonlyNode != null)
-				Readonly = FieldLoader.GetValue<bool>("Readonly", readonlyNode.Value.Value);
+			if (nodeDict.TryGetValue("Readonly", out var readonlyYaml))
+				Readonly = FieldLoader.GetValue<bool>("Readonly", readonlyYaml.Value);
 		}
 	}
 }
diff --git a/OpenRA.Game/Manifest.cs b/OpenRA.Game/Manifest.cs
index 4405cfc684..8f3da202da 100644
--- a/OpenRA.Game/Manifest.cs
+++ b/OpenRA.Game/Manifest.cs
@@ -214,7 +214,7 @@ namespace OpenRA
 			if (!yaml.ContainsKey(key))
 				return Array.Empty<string>();
 
-			return yaml[key].ToDictionary().Keys.ToArray();
+			return yaml[key].Nodes.Select(n => n.Key).ToArray();
 		}
 
 		static IReadOnlyDictionary<string, string> YamlDictionary(Dictionary<string, MiniYaml> yaml, string key)
diff --git a/OpenRA.Game/Map/Map.cs b/OpenRA.Game/Map/Map.cs
index 2b386c1576..f506b2e733 100644
--- a/OpenRA.Game/Map/Map.cs
+++ b/OpenRA.Game/Map/Map.cs
@@ -95,9 +95,9 @@ namespace OpenRA
 				t == typeof(MiniYaml) ? Type.MiniYaml : Type.Normal;
 		}
 
-		public void Deserialize(Map map, ImmutableArray<MiniYamlNode> nodes)
+		public void Deserialize(Map map, MiniYaml yaml)
 		{
-			var node = nodes.FirstOrDefault(n => n.Key == key);
+			var node = yaml.NodeWithKeyOrDefault(key);
 			if (node == null)
 			{
 				if (required)
@@ -363,13 +363,13 @@ namespace OpenRA
 
 			var yaml = new MiniYaml(null, MiniYaml.FromStream(Package.GetStream("map.yaml"), package.Name));
 			foreach (var field in YamlFields)
-				field.Deserialize(this, yaml.Nodes);
+				field.Deserialize(this, yaml);
 
 			if (MapFormat < SupportedMapFormat)
 				throw new InvalidDataException($"Map format {MapFormat} is not supported.\n File: {package.Name}");
 
-			PlayerDefinitions = MiniYaml.NodesOrEmpty(yaml, "Players");
-			ActorDefinitions = MiniYaml.NodesOrEmpty(yaml, "Actors");
+			PlayerDefinitions = yaml.NodeWithKeyOrDefault("Players")?.Value.Nodes ?? ImmutableArray<MiniYamlNode>.Empty;
+			ActorDefinitions = yaml.NodeWithKeyOrDefault("Actors")?.Value.Nodes ?? ImmutableArray<MiniYamlNode>.Empty;
 
 			Grid = modData.Manifest.Get<MapGrid>();
 
diff --git a/OpenRA.Game/MiniYaml.cs b/OpenRA.Game/MiniYaml.cs
index a28ca60fd0..7807389a7b 100644
--- a/OpenRA.Game/MiniYaml.cs
+++ b/OpenRA.Game/MiniYaml.cs
@@ -141,6 +141,34 @@ namespace OpenRA
 			return new MiniYaml(Value, newNodes);
 		}
 
+		public MiniYamlNode NodeWithKey(string key)
+		{
+			var result = NodeWithKeyOrDefault(key);
+			if (result == null)
+				throw new InvalidDataException($"No node with key '{key}'");
+			return result;
+		}
+
+		public MiniYamlNode NodeWithKeyOrDefault(string key)
+		{
+			// PERF: Avoid LINQ.
+			var first = true;
+			MiniYamlNode result = null;
+			foreach (var node in Nodes)
+			{
+				if (node.Key != key)
+					continue;
+
+				if (!first)
+					throw new InvalidDataException($"Duplicate key '{node.Key}' in {node.Location}");
+
+				first = false;
+				result = node;
+			}
+
+			return result;
+		}
+
 		public Dictionary<string, MiniYaml> ToDictionary()
 		{
 			return ToDictionary(MiniYamlIdentity);
@@ -175,11 +203,6 @@ namespace OpenRA
 			Nodes = ImmutableArray.CreateRange(nodes);
 		}
 
-		public static ImmutableArray<MiniYamlNode> NodesOrEmpty(MiniYaml y, string s)
-		{
-			return y.Nodes.FirstOrDefault(n => n.Key == s)?.Value.Nodes ?? ImmutableArray<MiniYamlNode>.Empty;
-		}
-
 		static List<MiniYamlNode> FromLines(IEnumerable<ReadOnlyMemory<char>> lines, string filename, bool discardCommentsAndWhitespace, Dictionary<string, string> stringPool)
 		{
 			stringPool ??= new Dictionary<string, string>();
@@ -668,6 +691,11 @@ namespace OpenRA
 				foreach (var line in Nodes.ToLines())
 					yield return "\t" + line;
 		}
+
+		public MiniYamlNodeBuilder NodeWithKeyOrDefault(string key)
+		{
+			return Nodes.SingleOrDefault(n => n.Key == key);
+		}
 	}
 
 	[Serializable]
diff --git a/OpenRA.Game/Network/GameServer.cs b/OpenRA.Game/Network/GameServer.cs
index 63d9c11aa3..7a7b766b18 100644
--- a/OpenRA.Game/Network/GameServer.cs
+++ b/OpenRA.Game/Network/GameServer.cs
@@ -140,7 +140,7 @@ namespace OpenRA.Network
 		static object LoadClients(MiniYaml yaml)
 		{
 			var clients = new List<GameClient>();
-			var clientsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Clients");
+			var clientsNode = yaml.NodeWithKeyOrDefault("Clients");
 			if (clientsNode != null)
 			{
 				var regex = new Regex(@"Client@\d+");
@@ -159,7 +159,7 @@ namespace OpenRA.Network
 			// Games advertised using the old API used a single Mods field
 			if (Mod == null || Version == null)
 			{
-				var modsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Mods");
+				var modsNode = yaml.NodeWithKeyOrDefault("Mods");
 				if (modsNode != null)
 				{
 					var modVersion = modsNode.Value.Value.Split('@');
diff --git a/OpenRA.Game/Network/LocalizedMessage.cs b/OpenRA.Game/Network/LocalizedMessage.cs
index 4deb7b7330..3a0feaa9ca 100644
--- a/OpenRA.Game/Network/LocalizedMessage.cs
+++ b/OpenRA.Game/Network/LocalizedMessage.cs
@@ -60,7 +60,7 @@ namespace OpenRA.Network
 		static object LoadArguments(MiniYaml yaml)
 		{
 			var arguments = new Dictionary<string, object>();
-			var argumentsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Arguments");
+			var argumentsNode = yaml.NodeWithKeyOrDefault("Arguments");
 			if (argumentsNode != null)
 			{
 				foreach (var argumentNode in argumentsNode.Value.Nodes)
diff --git a/OpenRA.Game/Network/Session.cs b/OpenRA.Game/Network/Session.cs
index 1c7b21b293..c916e700c8 100644
--- a/OpenRA.Game/Network/Session.cs
+++ b/OpenRA.Game/Network/Session.cs
@@ -227,7 +227,7 @@ namespace OpenRA.Network
 			{
 				var gs = FieldLoader.Load<Global>(data);
 
-				var optionsNode = data.Nodes.FirstOrDefault(n => n.Key == "Options");
+				var optionsNode = data.NodeWithKeyOrDefault("Options");
 				if (optionsNode != null)
 					foreach (var n in optionsNode.Value.Nodes)
 						gs.LobbyOptions[n.Key] = FieldLoader.Load<LobbyOptionState>(n.Value);
diff --git a/OpenRA.Game/PlayerDatabase.cs b/OpenRA.Game/PlayerDatabase.cs
index 3a98f5aaa9..c02895d09a 100644
--- a/OpenRA.Game/PlayerDatabase.cs
+++ b/OpenRA.Game/PlayerDatabase.cs
@@ -9,7 +9,6 @@
  */
 #endregion
 
-using System.Linq;
 using System.Threading.Tasks;
 using OpenRA.FileFormats;
 using OpenRA.Graphics;
@@ -94,10 +93,10 @@ namespace OpenRA
 				});
 			}
 
-			var labelNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Label");
-			var icon24Node = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon24");
-			var icon48Node = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon48");
-			var icon72Node = yaml.Nodes.FirstOrDefault(n => n.Key == "Icon72");
+			var labelNode = yaml.NodeWithKeyOrDefault("Label");
+			var icon24Node = yaml.NodeWithKeyOrDefault("Icon24");
+			var icon48Node = yaml.NodeWithKeyOrDefault("Icon48");
+			var icon72Node = yaml.NodeWithKeyOrDefault("Icon72");
 			if (labelNode == null)
 				return null;
 
diff --git a/OpenRA.Game/PlayerProfile.cs b/OpenRA.Game/PlayerProfile.cs
index d8c72c53bc..b9a74a8efd 100644
--- a/OpenRA.Game/PlayerProfile.cs
+++ b/OpenRA.Game/PlayerProfile.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Linq;
 
 namespace OpenRA
 {
@@ -31,7 +30,7 @@ namespace OpenRA
 		{
 			var badges = new List<PlayerBadge>();
 
-			var badgesNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Badges");
+			var badgesNode = yaml.NodeWithKeyOrDefault("Badges");
 			if (badgesNode != null)
 			{
 				var playerDatabase = Game.ModData.Manifest.Get<PlayerDatabase>();
diff --git a/OpenRA.Game/Settings.cs b/OpenRA.Game/Settings.cs
index e7e5847db5..11c7de0a3f 100644
--- a/OpenRA.Game/Settings.cs
+++ b/OpenRA.Game/Settings.cs
@@ -385,7 +385,7 @@ namespace OpenRA
 					else
 					{
 						// Update or add the custom value
-						var fieldYaml = sectionYaml.Value.Nodes.FirstOrDefault(n => n.Key == fli.YamlName);
+						var fieldYaml = sectionYaml.Value.NodeWithKeyOrDefault(fli.YamlName);
 						if (fieldYaml != null)
 							fieldYaml.Value.Value = serialized;
 						else
diff --git a/OpenRA.Game/Traits/TraitsInterfaces.cs b/OpenRA.Game/Traits/TraitsInterfaces.cs
index 57154dc125..b0923d3c63 100644
--- a/OpenRA.Game/Traits/TraitsInterfaces.cs
+++ b/OpenRA.Game/Traits/TraitsInterfaces.cs
@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Collections.ObjectModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
@@ -350,7 +349,7 @@ namespace OpenRA.Traits
 	public interface IGameSaveTraitData
 	{
 		List<MiniYamlNode> IssueTraitData(Actor self);
-		void ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data);
+		void ResolveTraitData(Actor self, MiniYaml data);
 	}
 
 	[RequireExplicitImplementation]
diff --git a/OpenRA.Game/Widgets/WidgetLoader.cs b/OpenRA.Game/Widgets/WidgetLoader.cs
index af402b5363..8cdbdb0777 100644
--- a/OpenRA.Game/Widgets/WidgetLoader.cs
+++ b/OpenRA.Game/Widgets/WidgetLoader.cs
@@ -66,7 +66,7 @@ namespace OpenRA
 					foreach (var c in child.Value.Nodes)
 						LoadWidget(args, widget, c);
 
-			var logicNode = node.Value.Nodes.FirstOrDefault(n => n.Key == "Logic");
+			var logicNode = node.Value.NodeWithKeyOrDefault("Logic");
 			var logic = logicNode?.Value.ToDictionary();
 			args.Add("logicArgs", logic);
 
diff --git a/OpenRA.Game/World.cs b/OpenRA.Game/World.cs
index d4b3d27793..6a69c15aee 100644
--- a/OpenRA.Game/World.cs
+++ b/OpenRA.Game/World.cs
@@ -423,7 +423,7 @@ namespace OpenRA
 					if (tp.Actor == null)
 						break;
 
-					tp.Trait.ResolveTraitData(tp.Actor, kv.Value.Nodes);
+					tp.Trait.ResolveTraitData(tp.Actor, kv.Value);
 				}
 
 				gameSaveTraitData.Clear();
diff --git a/OpenRA.Mods.Cnc/Graphics/ClassicTilesetSpecificSpriteSequence.cs b/OpenRA.Mods.Cnc/Graphics/ClassicTilesetSpecificSpriteSequence.cs
index b0ed9dcc0d..783290cfe1 100644
--- a/OpenRA.Mods.Cnc/Graphics/ClassicTilesetSpecificSpriteSequence.cs
+++ b/OpenRA.Mods.Cnc/Graphics/ClassicTilesetSpecificSpriteSequence.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Graphics;
 
@@ -39,10 +38,10 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 		protected override IEnumerable<ReservationInfo> ParseFilenames(ModData modData, string tileset, int[] frames, MiniYaml data, MiniYaml defaults)
 		{
-			var node = data.Nodes.FirstOrDefault(n => n.Key == TilesetFilenames.Key) ?? defaults.Nodes.FirstOrDefault(n => n.Key == TilesetFilenames.Key);
+			var node = data.NodeWithKeyOrDefault(TilesetFilenames.Key) ?? defaults.NodeWithKeyOrDefault(TilesetFilenames.Key);
 			if (node != null)
 			{
-				var tilesetNode = node.Value.Nodes.FirstOrDefault(n => n.Key == tileset);
+				var tilesetNode = node.Value.NodeWithKeyOrDefault(tileset);
 				if (tilesetNode != null)
 				{
 					var loadFrames = CalculateFrameIndices(start, length, stride ?? length ?? 0, facings, frames, transpose, reverseFacings, shadowStart);
@@ -55,10 +54,10 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 		protected override IEnumerable<ReservationInfo> ParseCombineFilenames(ModData modData, string tileset, int[] frames, MiniYaml data)
 		{
-			var node = data.Nodes.FirstOrDefault(n => n.Key == TilesetFilenames.Key);
+			var node = data.NodeWithKeyOrDefault(TilesetFilenames.Key);
 			if (node != null)
 			{
-				var tilesetNode = node.Value.Nodes.FirstOrDefault(n => n.Key == tileset);
+				var tilesetNode = node.Value.NodeWithKeyOrDefault(tileset);
 				if (tilesetNode != null)
 				{
 					if (frames == null)
diff --git a/OpenRA.Mods.Cnc/UtilityCommands/ImportGen1MapCommand.cs b/OpenRA.Mods.Cnc/UtilityCommands/ImportGen1MapCommand.cs
index acbff3e9d0..1f2ae3deca 100644
--- a/OpenRA.Mods.Cnc/UtilityCommands/ImportGen1MapCommand.cs
+++ b/OpenRA.Mods.Cnc/UtilityCommands/ImportGen1MapCommand.cs
@@ -130,7 +130,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 
 		protected MiniYamlNodeBuilder GetWorldNodeBuilderFromRules()
 		{
-			var worldNode = Map.RuleDefinitions.Nodes.FirstOrDefault(n => n.Key == "World");
+			var worldNode = Map.RuleDefinitions.NodeWithKeyOrDefault("World");
 			var worldNodeBuilder = worldNode != null
 				? new MiniYamlNodeBuilder(worldNode)
 				: new MiniYamlNodeBuilder("World", new MiniYamlBuilder("", new List<MiniYamlNode>()));
@@ -166,7 +166,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 
 			var worldNodeBuilder = GetWorldNodeBuilderFromRules();
 
-			var missionData = worldNodeBuilder.Value.Nodes.FirstOrDefault(n => n.Key == "MissionData");
+			var missionData = worldNodeBuilder.Value.NodeWithKeyOrDefault("MissionData");
 			if (missionData == null)
 			{
 				missionData = new MiniYamlNodeBuilder("MissionData", new MiniYamlBuilder("", new List<MiniYamlNode>()));
@@ -237,7 +237,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 			{
 				var worldNodeBuilder = GetWorldNodeBuilderFromRules();
 
-				var missionData = worldNodeBuilder.Value.Nodes.FirstOrDefault(n => n.Key == "MissionData");
+				var missionData = worldNodeBuilder.Value.NodeWithKeyOrDefault("MissionData");
 				if (missionData == null)
 				{
 					missionData = new MiniYamlNodeBuilder("MissionData", new MiniYamlBuilder("", new List<MiniYamlNode>()));
diff --git a/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs b/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs
index 0f70ece2ff..5fbc5cb0c8 100644
--- a/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs
+++ b/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs
@@ -47,7 +47,7 @@ namespace OpenRA.Mods.Common.Graphics
 		IReadOnlyDictionary<string, ISpriteSequence> ISpriteSequenceLoader.ParseSequences(ModData modData, string tileset, SpriteCache cache, MiniYamlNode imageNode)
 		{
 			var sequences = new Dictionary<string, ISpriteSequence>();
-			var node = imageNode.Value.Nodes.SingleOrDefault(n => n.Key == "Defaults");
+			var node = imageNode.Value.NodeWithKeyOrDefault("Defaults");
 			var defaults = node?.Value ?? NoData;
 			imageNode = imageNode.WithValue(imageNode.Value.WithNodes(imageNode.Value.Nodes.Remove(node)));
 
@@ -262,7 +262,7 @@ namespace OpenRA.Mods.Common.Graphics
 
 		protected static T LoadField<T>(string key, T fallback, MiniYaml data, MiniYaml defaults = null)
 		{
-			var node = data.Nodes.FirstOrDefault(n => n.Key == key) ?? defaults?.Nodes.FirstOrDefault(n => n.Key == key);
+			var node = data.NodeWithKeyOrDefault(key) ?? defaults?.NodeWithKeyOrDefault(key);
 			if (node == null)
 				return fallback;
 
@@ -276,7 +276,7 @@ namespace OpenRA.Mods.Common.Graphics
 
 		protected static T LoadField<T>(SpriteSequenceField<T> field, MiniYaml data, MiniYaml defaults, out MiniYamlNode.SourceLocation location)
 		{
-			var node = data.Nodes.FirstOrDefault(n => n.Key == field.Key) ?? defaults?.Nodes.FirstOrDefault(n => n.Key == field.Key);
+			var node = data.NodeWithKeyOrDefault(field.Key) ?? defaults?.NodeWithKeyOrDefault(field.Key);
 			if (node == null)
 			{
 				location = default;
@@ -414,7 +414,7 @@ namespace OpenRA.Mods.Common.Graphics
 			var offset = LoadField(Offset, data, defaults);
 			var blendMode = LoadField(BlendMode, data, defaults);
 
-			var combineNode = data.Nodes.FirstOrDefault(n => n.Key == Combine.Key);
+			var combineNode = data.NodeWithKeyOrDefault(Combine.Key);
 			if (combineNode != null)
 			{
 				for (var i = 0; i < combineNode.Value.Nodes.Length; i++)
diff --git a/OpenRA.Mods.Common/Graphics/TilesetSpecificSpriteSequence.cs b/OpenRA.Mods.Common/Graphics/TilesetSpecificSpriteSequence.cs
index d1f3b49b35..40046118d6 100644
--- a/OpenRA.Mods.Common/Graphics/TilesetSpecificSpriteSequence.cs
+++ b/OpenRA.Mods.Common/Graphics/TilesetSpecificSpriteSequence.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Graphics;
 
 namespace OpenRA.Mods.Common.Graphics
@@ -37,10 +36,10 @@ namespace OpenRA.Mods.Common.Graphics
 
 		protected override IEnumerable<ReservationInfo> ParseFilenames(ModData modData, string tileset, int[] frames, MiniYaml data, MiniYaml defaults)
 		{
-			var node = data.Nodes.FirstOrDefault(n => n.Key == TilesetFilenames.Key) ?? defaults.Nodes.FirstOrDefault(n => n.Key == TilesetFilenames.Key);
+			var node = data.NodeWithKeyOrDefault(TilesetFilenames.Key) ?? defaults.NodeWithKeyOrDefault(TilesetFilenames.Key);
 			if (node != null)
 			{
-				var tilesetNode = node.Value.Nodes.FirstOrDefault(n => n.Key == tileset);
+				var tilesetNode = node.Value.NodeWithKeyOrDefault(tileset);
 				if (tilesetNode != null)
 				{
 					var loadFrames = CalculateFrameIndices(start, length, stride ?? length ?? 0, facings, frames, transpose, reverseFacings, shadowStart);
@@ -53,10 +52,10 @@ namespace OpenRA.Mods.Common.Graphics
 
 		protected override IEnumerable<ReservationInfo> ParseCombineFilenames(ModData modData, string tileset, int[] frames, MiniYaml data)
 		{
-			var node = data.Nodes.FirstOrDefault(n => n.Key == TilesetFilenames.Key);
+			var node = data.NodeWithKeyOrDefault(TilesetFilenames.Key);
 			if (node != null)
 			{
-				var tilesetNode = node.Value.Nodes.FirstOrDefault(n => n.Key == tileset);
+				var tilesetNode = node.Value.NodeWithKeyOrDefault(tileset);
 				if (tilesetNode != null)
 				{
 					if (frames == null)
diff --git a/OpenRA.Mods.Common/Installer/InstallerUtils.cs b/OpenRA.Mods.Common/Installer/InstallerUtils.cs
index 726da2ac01..fd711ba9e4 100644
--- a/OpenRA.Mods.Common/Installer/InstallerUtils.cs
+++ b/OpenRA.Mods.Common/Installer/InstallerUtils.cs
@@ -11,7 +11,6 @@
 
 using System;
 using System.IO;
-using System.Linq;
 using FS = OpenRA.FileSystem.FileSystem;
 
 namespace OpenRA.Mods.Common.Installer
@@ -33,8 +32,8 @@ namespace OpenRA.Mods.Common.Installer
 
 					using (var fileStream = File.OpenRead(filePath))
 					{
-						var offsetNode = kv.Value.Nodes.FirstOrDefault(n => n.Key == "Offset");
-						var lengthNode = kv.Value.Nodes.FirstOrDefault(n => n.Key == "Length");
+						var offsetNode = kv.Value.NodeWithKeyOrDefault("Offset");
+						var lengthNode = kv.Value.NodeWithKeyOrDefault("Length");
 						if (offsetNode != null || lengthNode != null)
 						{
 							var offset = 0L;
diff --git a/OpenRA.Mods.Common/Installer/SourceActions/ExtractIscabSourceAction.cs b/OpenRA.Mods.Common/Installer/SourceActions/ExtractIscabSourceAction.cs
index 08dd1acc5d..1a497bfae3 100644
--- a/OpenRA.Mods.Common/Installer/SourceActions/ExtractIscabSourceAction.cs
+++ b/OpenRA.Mods.Common/Installer/SourceActions/ExtractIscabSourceAction.cs
@@ -12,7 +12,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using OpenRA.Mods.Common.FileFormats;
 using OpenRA.Mods.Common.Widgets.Logic;
 using FS = OpenRA.FileSystem.FileSystem;
@@ -26,11 +25,11 @@ namespace OpenRA.Mods.Common.Installer
 			// Yaml path may be specified relative to a named directory (e.g. ^SupportDir) or the detected source path
 			var sourcePath = actionYaml.Value.StartsWith('^') ? Platform.ResolvePath(actionYaml.Value) : FS.ResolveCaseInsensitivePath(Path.Combine(path, actionYaml.Value));
 
-			var volumeNode = actionYaml.Nodes.FirstOrDefault(n => n.Key == "Volumes");
+			var volumeNode = actionYaml.NodeWithKeyOrDefault("Volumes");
 			if (volumeNode == null)
 				throw new InvalidDataException("extract-iscab entry doesn't define a Volumes node");
 
-			var extractNode = actionYaml.Nodes.FirstOrDefault(n => n.Key == "Extract");
+			var extractNode = actionYaml.NodeWithKeyOrDefault("Extract");
 			if (extractNode == null)
 				throw new InvalidDataException("extract-iscab entry doesn't define an Extract node");
 
diff --git a/OpenRA.Mods.Common/Installer/SourceActions/ExtractRawSourceAction.cs b/OpenRA.Mods.Common/Installer/SourceActions/ExtractRawSourceAction.cs
index 70c0f4e9ba..4a237c28d6 100644
--- a/OpenRA.Mods.Common/Installer/SourceActions/ExtractRawSourceAction.cs
+++ b/OpenRA.Mods.Common/Installer/SourceActions/ExtractRawSourceAction.cs
@@ -12,7 +12,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using OpenRA.Mods.Common.Widgets.Logic;
 using FS = OpenRA.FileSystem.FileSystem;
 
@@ -37,14 +36,14 @@ namespace OpenRA.Mods.Common.Installer
 						continue;
 					}
 
-					var offsetNode = node.Value.Nodes.FirstOrDefault(n => n.Key == "Offset");
+					var offsetNode = node.Value.NodeWithKeyOrDefault("Offset");
 					if (offsetNode == null)
 					{
 						Log.Write("install", "Skipping entry with missing Offset definition " + targetPath);
 						continue;
 					}
 
-					var lengthNode = node.Value.Nodes.FirstOrDefault(n => n.Key == "Length");
+					var lengthNode = node.Value.NodeWithKeyOrDefault("Length");
 					if (lengthNode == null)
 					{
 						Log.Write("install", "Skipping entry with missing Length definition " + targetPath);
diff --git a/OpenRA.Mods.Common/Installer/SourceResolvers/GogSourceResolver.cs b/OpenRA.Mods.Common/Installer/SourceResolvers/GogSourceResolver.cs
index 0a7c8323b7..29d7c2b900 100644
--- a/OpenRA.Mods.Common/Installer/SourceResolvers/GogSourceResolver.cs
+++ b/OpenRA.Mods.Common/Installer/SourceResolvers/GogSourceResolver.cs
@@ -18,7 +18,7 @@ namespace OpenRA.Mods.Common.Installer
 	{
 		public string FindSourcePath(ModContent.ModSource modSource)
 		{
-			modSource.Type.ToDictionary().TryGetValue("AppId", out var appId);
+			var appId = modSource.Type.NodeWithKeyOrDefault("AppId");
 
 			if (appId == null)
 				return null;
@@ -35,7 +35,7 @@ namespace OpenRA.Mods.Common.Installer
 
 			foreach (var prefix in prefixes)
 			{
-				if (Registry.GetValue($"{prefix}GOG.com\\Games\\{appId.Value}", "path", null) is not string installDir)
+				if (Registry.GetValue($"{prefix}GOG.com\\Games\\{appId.Value.Value}", "path", null) is not string installDir)
 					continue;
 
 				if (InstallerUtils.IsValidSourcePath(installDir, modSource))
diff --git a/OpenRA.Mods.Common/Installer/SourceResolvers/SteamSourceResolver.cs b/OpenRA.Mods.Common/Installer/SourceResolvers/SteamSourceResolver.cs
index 712bdd1f8d..a2d1e85968 100644
--- a/OpenRA.Mods.Common/Installer/SourceResolvers/SteamSourceResolver.cs
+++ b/OpenRA.Mods.Common/Installer/SourceResolvers/SteamSourceResolver.cs
@@ -23,14 +23,14 @@ namespace OpenRA.Mods.Common.Installer
 	{
 		public string FindSourcePath(ModContent.ModSource modSource)
 		{
-			modSource.Type.ToDictionary().TryGetValue("AppId", out var appId);
+			var appId = modSource.Type.NodeWithKeyOrDefault("AppId");
 
 			if (appId == null)
 				return null;
 
 			foreach (var steamDirectory in SteamDirectory())
 			{
-				var manifestPath = Path.Combine(steamDirectory, "steamapps", $"appmanifest_{appId.Value}.acf");
+				var manifestPath = Path.Combine(steamDirectory, "steamapps", $"appmanifest_{appId.Value.Value}.acf");
 
 				if (!File.Exists(manifestPath))
 					continue;
diff --git a/OpenRA.Mods.Common/Lint/CheckCursors.cs b/OpenRA.Mods.Common/Lint/CheckCursors.cs
index 43d3ebd39a..76f58b3f1a 100644
--- a/OpenRA.Mods.Common/Lint/CheckCursors.cs
+++ b/OpenRA.Mods.Common/Lint/CheckCursors.cs
@@ -33,11 +33,11 @@ namespace OpenRA.Mods.Common.Lint
 		{
 			var fileSystem = modData.DefaultFileSystem;
 			var sequenceYaml = MiniYaml.Merge(modData.Manifest.Cursors.Select(s => MiniYaml.FromStream(fileSystem.Open(s), s)));
-			var nodesDict = new MiniYaml(null, sequenceYaml).ToDictionary();
+			var cursorsYaml = new MiniYaml(null, sequenceYaml).NodeWithKey("Cursors").Value;
 
 			// Avoid using CursorProvider as it attempts to load palettes from the file system.
 			var cursors = new List<string>();
-			foreach (var s in nodesDict["Cursors"].Nodes)
+			foreach (var s in cursorsYaml.Nodes)
 				foreach (var sequence in s.Value.Nodes)
 					cursors.Add(sequence.Key);
 
diff --git a/OpenRA.Mods.Common/ModContent.cs b/OpenRA.Mods.Common/ModContent.cs
index f5358b6397..81fcab8fde 100644
--- a/OpenRA.Mods.Common/ModContent.cs
+++ b/OpenRA.Mods.Common/ModContent.cs
@@ -66,15 +66,15 @@ namespace OpenRA
 				ObjectCreator = objectCreator;
 				Title = yaml.Value;
 
-				var type = yaml.Nodes.FirstOrDefault(n => n.Key == "Type");
+				var type = yaml.NodeWithKeyOrDefault("Type");
 				if (type != null)
 					Type = type.Value;
 
-				var idFiles = yaml.Nodes.FirstOrDefault(n => n.Key == "IDFiles");
+				var idFiles = yaml.NodeWithKeyOrDefault("IDFiles");
 				if (idFiles != null)
 					IDFiles = idFiles.Value;
 
-				var installNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Install");
+				var installNode = yaml.NodeWithKeyOrDefault("Install");
 				if (installNode != null)
 					Install = installNode.Value.Nodes;
 
@@ -111,7 +111,7 @@ namespace OpenRA
 		static object LoadPackages(MiniYaml yaml)
 		{
 			var packages = new Dictionary<string, ModPackage>();
-			var packageNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Packages");
+			var packageNode = yaml.NodeWithKeyOrDefault("Packages");
 			if (packageNode != null)
 				foreach (var node in packageNode.Value.Nodes)
 					packages.Add(node.Key, new ModPackage(node.Value));
@@ -124,7 +124,7 @@ namespace OpenRA
 
 		static object LoadDownloads(MiniYaml yaml)
 		{
-			var downloadNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Downloads");
+			var downloadNode = yaml.NodeWithKeyOrDefault("Downloads");
 			return downloadNode != null ? downloadNode.Value.Nodes.Select(n => n.Key).ToArray() : Array.Empty<string>();
 		}
 
@@ -133,7 +133,7 @@ namespace OpenRA
 
 		static object LoadSources(MiniYaml yaml)
 		{
-			var sourceNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Sources");
+			var sourceNode = yaml.NodeWithKeyOrDefault("Sources");
 			return sourceNode != null ? sourceNode.Value.Nodes.Select(n => n.Key).ToArray() : Array.Empty<string>();
 		}
 	}
diff --git a/OpenRA.Mods.Common/Terrain/TerrainInfo.cs b/OpenRA.Mods.Common/Terrain/TerrainInfo.cs
index 7fcb834482..f0a06344f0 100644
--- a/OpenRA.Mods.Common/Terrain/TerrainInfo.cs
+++ b/OpenRA.Mods.Common/Terrain/TerrainInfo.cs
@@ -37,7 +37,7 @@ namespace OpenRA.Mods.Common.Terrain
 		{
 			FieldLoader.Load(this, my);
 
-			var nodes = my.ToDictionary()["Tiles"].Nodes;
+			var nodes = my.NodeWithKey("Tiles").Value.Nodes;
 
 			if (!PickAny)
 			{
diff --git a/OpenRA.Mods.Common/Traits/AppearsOnMapPreview.cs b/OpenRA.Mods.Common/Traits/AppearsOnMapPreview.cs
index 79e0149200..902fa40256 100644
--- a/OpenRA.Mods.Common/Traits/AppearsOnMapPreview.cs
+++ b/OpenRA.Mods.Common/Traits/AppearsOnMapPreview.cs
@@ -41,7 +41,7 @@ namespace OpenRA.Mods.Common.Traits
 			else
 			{
 				var owner = map.PlayerDefinitions.Single(p => s.Get<OwnerInit>().InternalName == p.Value.Nodes.Last(k => k.Key == "Name").Value.Value);
-				var colorValue = owner.Value.Nodes.FirstOrDefault(n => n.Key == "Color");
+				var colorValue = owner.Value.NodeWithKeyOrDefault("Color");
 				var ownerColor = colorValue?.Value.Value ?? "FFFFFF";
 				Color.TryParse(ownerColor, out color);
 			}
diff --git a/OpenRA.Mods.Common/Traits/BotModules/BaseBuilderBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/BaseBuilderBotModule.cs
index 9edb861aca..67ba202ec0 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/BaseBuilderBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/BaseBuilderBotModule.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Traits;
 
@@ -326,16 +325,16 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
 			if (self.World.IsReplay)
 				return;
 
-			var initialBaseCenterNode = data.FirstOrDefault(n => n.Key == "InitialBaseCenter");
+			var initialBaseCenterNode = data.NodeWithKeyOrDefault("InitialBaseCenter");
 			if (initialBaseCenterNode != null)
 				initialBaseCenter = FieldLoader.GetValue<CPos>("InitialBaseCenter", initialBaseCenterNode.Value.Value);
 
-			var defenseCenterNode = data.FirstOrDefault(n => n.Key == "DefenseCenter");
+			var defenseCenterNode = data.NodeWithKeyOrDefault("DefenseCenter");
 			if (defenseCenterNode != null)
 				DefenseCenter = FieldLoader.GetValue<CPos>("DefenseCenter", defenseCenterNode.Value.Value);
 		}
diff --git a/OpenRA.Mods.Common/Traits/BotModules/McvManagerBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/McvManagerBotModule.cs
index 3aa3c0514a..ebb5b8f0ae 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/McvManagerBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/McvManagerBotModule.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Traits;
 
@@ -213,12 +212,12 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
 			if (self.World.IsReplay)
 				return;
 
-			var initialBaseCenterNode = data.FirstOrDefault(n => n.Key == "InitialBaseCenter");
+			var initialBaseCenterNode = data.NodeWithKeyOrDefault("InitialBaseCenter");
 			if (initialBaseCenterNode != null)
 				initialBaseCenter = FieldLoader.GetValue<CPos>("InitialBaseCenter", initialBaseCenterNode.Value.Value);
 		}
diff --git a/OpenRA.Mods.Common/Traits/BotModules/SquadManagerBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/SquadManagerBotModule.cs
index 6793bedda0..ca5588f8b3 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/SquadManagerBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/SquadManagerBotModule.cs
@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Mods.Common.Traits.BotModules.Squads;
 using OpenRA.Primitives;
@@ -526,52 +525,46 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
 			if (self.World.IsReplay)
 				return;
 
-			var initialBaseCenterNode = data.FirstOrDefault(n => n.Key == "InitialBaseCenter");
-			if (initialBaseCenterNode != null)
-				initialBaseCenter = FieldLoader.GetValue<CPos>("InitialBaseCenter", initialBaseCenterNode.Value.Value);
+			var nodes = data.ToDictionary();
 
-			var unitsHangingAroundTheBaseNode = data.FirstOrDefault(n => n.Key == "UnitsHangingAroundTheBase");
-			if (unitsHangingAroundTheBaseNode != null)
+			if (nodes.TryGetValue("InitialBaseCenter", out var initialBaseCenterNode))
+				initialBaseCenter = FieldLoader.GetValue<CPos>("InitialBaseCenter", initialBaseCenterNode.Value);
+
+			if (nodes.TryGetValue("UnitsHangingAroundTheBase", out var unitsHangingAroundTheBaseNode))
 			{
 				unitsHangingAroundTheBase.Clear();
-				unitsHangingAroundTheBase.AddRange(FieldLoader.GetValue<uint[]>("UnitsHangingAroundTheBase", unitsHangingAroundTheBaseNode.Value.Value)
+				unitsHangingAroundTheBase.AddRange(FieldLoader.GetValue<uint[]>("UnitsHangingAroundTheBase", unitsHangingAroundTheBaseNode.Value)
 					.Select(a => self.World.GetActorById(a)).Where(a => a != null));
 			}
 
-			var activeUnitsNode = data.FirstOrDefault(n => n.Key == "ActiveUnits");
-			if (activeUnitsNode != null)
+			if (nodes.TryGetValue("ActiveUnits", out var activeUnitsNode))
 			{
 				activeUnits.Clear();
-				activeUnits.UnionWith(FieldLoader.GetValue<uint[]>("ActiveUnits", activeUnitsNode.Value.Value)
+				activeUnits.UnionWith(FieldLoader.GetValue<uint[]>("ActiveUnits", activeUnitsNode.Value)
 					.Select(a => self.World.GetActorById(a)).Where(a => a != null));
 			}
 
-			var rushTicksNode = data.FirstOrDefault(n => n.Key == "RushTicks");
-			if (rushTicksNode != null)
-				rushTicks = FieldLoader.GetValue<int>("RushTicks", rushTicksNode.Value.Value);
+			if (nodes.TryGetValue("RushTicks", out var rushTicksNode))
+				rushTicks = FieldLoader.GetValue<int>("RushTicks", rushTicksNode.Value);
 
-			var assignRolesTicksNode = data.FirstOrDefault(n => n.Key == "AssignRolesTicks");
-			if (assignRolesTicksNode != null)
-				assignRolesTicks = FieldLoader.GetValue<int>("AssignRolesTicks", assignRolesTicksNode.Value.Value);
+			if (nodes.TryGetValue("AssignRolesTicks", out var assignRolesTicksNode))
+				assignRolesTicks = FieldLoader.GetValue<int>("AssignRolesTicks", assignRolesTicksNode.Value);
 
-			var attackForceTicksNode = data.FirstOrDefault(n => n.Key == "AttackForceTicks");
-			if (attackForceTicksNode != null)
-				attackForceTicks = FieldLoader.GetValue<int>("AttackForceTicks", attackForceTicksNode.Value.Value);
+			if (nodes.TryGetValue("AttackForceTicks", out var attackForceTicksNode))
+				attackForceTicks = FieldLoader.GetValue<int>("AttackForceTicks", attackForceTicksNode.Value);
 
-			var minAttackForceDelayTicksNode = data.FirstOrDefault(n => n.Key == "MinAttackForceDelayTicks");
-			if (minAttackForceDelayTicksNode != null)
-				minAttackForceDelayTicks = FieldLoader.GetValue<int>("MinAttackForceDelayTicks", minAttackForceDelayTicksNode.Value.Value);
+			if (nodes.TryGetValue("MinAttackForceDelayTicks", out var minAttackForceDelayTicksNode))
+				minAttackForceDelayTicks = FieldLoader.GetValue<int>("MinAttackForceDelayTicks", minAttackForceDelayTicksNode.Value);
 
-			var squadsNode = data.FirstOrDefault(n => n.Key == "Squads");
-			if (squadsNode != null)
+			if (nodes.TryGetValue("Squads", out var squadsNode))
 			{
 				Squads.Clear();
-				foreach (var n in squadsNode.Value.Nodes)
+				foreach (var n in squadsNode.Nodes)
 					Squads.Add(Squad.Deserialize(bot, this, n.Value));
 			}
 		}
diff --git a/OpenRA.Mods.Common/Traits/BotModules/Squads/Squad.cs b/OpenRA.Mods.Common/Traits/BotModules/Squads/Squad.cs
index 1b5f632be6..7afe09e31b 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/Squads/Squad.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/Squads/Squad.cs
@@ -155,12 +155,12 @@ namespace OpenRA.Mods.Common.Traits.BotModules.Squads
 			var type = SquadType.Rush;
 			var target = ((Actor)null, WVec.Zero);
 
-			var typeNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Type");
+			var typeNode = yaml.NodeWithKeyOrDefault("Type");
 			if (typeNode != null)
 				type = FieldLoader.GetValue<SquadType>("Type", typeNode.Value.Value);
 
-			var actorToTargetNode = yaml.Nodes.FirstOrDefault(n => n.Key == "ActorToTarget");
-			var targetOffsetNode = yaml.Nodes.FirstOrDefault(n => n.Key == "TargetOffset");
+			var actorToTargetNode = yaml.NodeWithKeyOrDefault("ActorToTarget");
+			var targetOffsetNode = yaml.NodeWithKeyOrDefault("TargetOffset");
 			if (actorToTargetNode != null && targetOffsetNode != null)
 			{
 				var actorToTarget = squadManager.World.GetActorById(FieldLoader.GetValue<uint>("ActorToTarget", actorToTargetNode.Value.Value));
@@ -170,7 +170,7 @@ namespace OpenRA.Mods.Common.Traits.BotModules.Squads
 
 			var squad = new Squad(bot, squadManager, type, target);
 
-			var unitsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Units");
+			var unitsNode = yaml.NodeWithKeyOrDefault("Units");
 			if (unitsNode != null)
 				squad.Units.UnionWith(FieldLoader.GetValue<uint[]>("Units", unitsNode.Value.Value)
 					.Select(a => squadManager.World.GetActorById(a)));
diff --git a/OpenRA.Mods.Common/Traits/BotModules/SupportPowerBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/SupportPowerBotModule.cs
index fe94e6f73e..079fc3c7fd 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/SupportPowerBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/SupportPowerBotModule.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Traits;
 
@@ -27,7 +26,7 @@ namespace OpenRA.Mods.Common.Traits
 		static object LoadDecisions(MiniYaml yaml)
 		{
 			var ret = new List<SupportPowerDecision>();
-			var decisions = yaml.Nodes.FirstOrDefault(n => n.Key == "Decisions");
+			var decisions = yaml.NodeWithKeyOrDefault("Decisions");
 			if (decisions != null)
 				foreach (var d in decisions.Value.Nodes)
 					ret.Add(new SupportPowerDecision(d.Value));
@@ -224,12 +223,12 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
 			if (self.World.IsReplay)
 				return;
 
-			var waitingPowersNode = data.FirstOrDefault(n => n.Key == "WaitingPowers");
+			var waitingPowersNode = data.NodeWithKeyOrDefault("WaitingPowers");
 			if (waitingPowersNode != null)
 			{
 				foreach (var n in waitingPowersNode.Value.Nodes)
diff --git a/OpenRA.Mods.Common/Traits/BotModules/UnitBuilderBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/UnitBuilderBotModule.cs
index 0d576c6e3f..7964b320f4 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/UnitBuilderBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/UnitBuilderBotModule.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Traits;
 
@@ -234,19 +233,19 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
 			if (self.World.IsReplay)
 				return;
 
-			var queuedBuildRequestsNode = data.FirstOrDefault(n => n.Key == "QueuedBuildRequests");
+			var queuedBuildRequestsNode = data.NodeWithKeyOrDefault("QueuedBuildRequests");
 			if (queuedBuildRequestsNode != null)
 			{
 				queuedBuildRequests.Clear();
 				queuedBuildRequests.AddRange(FieldLoader.GetValue<string[]>("QueuedBuildRequests", queuedBuildRequestsNode.Value.Value));
 			}
 
-			var idleUnitCountNode = data.FirstOrDefault(n => n.Key == "IdleUnitCount");
+			var idleUnitCountNode = data.NodeWithKeyOrDefault("IdleUnitCount");
 			if (idleUnitCountNode != null)
 				idleUnitCount = FieldLoader.GetValue<int>("IdleUnitCount", idleUnitCountNode.Value.Value);
 		}
diff --git a/OpenRA.Mods.Common/Traits/Buildings/Building.cs b/OpenRA.Mods.Common/Traits/Buildings/Building.cs
index ab14327a67..bf037e72d6 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/Building.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/Building.cs
@@ -64,10 +64,10 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected static object LoadFootprint(MiniYaml yaml)
 		{
-			var footprintYaml = yaml.Nodes.FirstOrDefault(n => n.Key == "Footprint");
+			var footprintYaml = yaml.NodeWithKeyOrDefault("Footprint");
 			var footprintChars = footprintYaml?.Value.Value.Where(x => !char.IsWhiteSpace(x)).ToArray() ?? new[] { 'x' };
 
-			var dimensionsYaml = yaml.Nodes.FirstOrDefault(n => n.Key == "Dimensions");
+			var dimensionsYaml = yaml.NodeWithKeyOrDefault("Dimensions");
 			var dim = dimensionsYaml != null ? FieldLoader.GetValue<CVec>("Dimensions", dimensionsYaml.Value.Value) : new CVec(1, 1);
 
 			if (footprintChars.Length != dim.X * dim.Y)
diff --git a/OpenRA.Mods.Common/Traits/HitShape.cs b/OpenRA.Mods.Common/Traits/HitShape.cs
index 467c20ea99..00c5039fcf 100644
--- a/OpenRA.Mods.Common/Traits/HitShape.cs
+++ b/OpenRA.Mods.Common/Traits/HitShape.cs
@@ -43,7 +43,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			IHitShape ret;
 
-			var shapeNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Type");
+			var shapeNode = yaml.NodeWithKeyOrDefault("Type");
 			var shape = shapeNode != null ? shapeNode.Value.Value : string.Empty;
 
 			if (!string.IsNullOrEmpty(shape))
diff --git a/OpenRA.Mods.Common/Traits/Player/GameSaveViewportManager.cs b/OpenRA.Mods.Common/Traits/Player/GameSaveViewportManager.cs
index 7f01f56347..6210d68578 100644
--- a/OpenRA.Mods.Common/Traits/Player/GameSaveViewportManager.cs
+++ b/OpenRA.Mods.Common/Traits/Player/GameSaveViewportManager.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Traits;
@@ -50,13 +49,13 @@ namespace OpenRA.Mods.Common.Traits
 			return nodes;
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
-			var viewportNode = data.FirstOrDefault(n => n.Key == "Viewport");
+			var viewportNode = data.NodeWithKeyOrDefault("Viewport");
 			if (viewportNode != null)
 				worldRenderer.Viewport.Center(FieldLoader.GetValue<WPos>("Viewport", viewportNode.Value.Value));
 
-			var renderPlayerNode = data.FirstOrDefault(n => n.Key == "RenderPlayer");
+			var renderPlayerNode = data.NodeWithKeyOrDefault("RenderPlayer");
 			if (renderPlayerNode != null)
 			{
 				var renderPlayerActorID = FieldLoader.GetValue<uint>("RenderPlayer", renderPlayerNode.Value.Value);
diff --git a/OpenRA.Mods.Common/Traits/World/ControlGroups.cs b/OpenRA.Mods.Common/Traits/World/ControlGroups.cs
index 3579b7d1a3..9022d37d30 100644
--- a/OpenRA.Mods.Common/Traits/World/ControlGroups.cs
+++ b/OpenRA.Mods.Common/Traits/World/ControlGroups.cs
@@ -133,9 +133,9 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
-			var groupsNode = data.FirstOrDefault(n => n.Key == "Groups");
+			var groupsNode = data.NodeWithKeyOrDefault("Groups");
 			if (groupsNode != null)
 			{
 				foreach (var n in groupsNode.Value.Nodes)
diff --git a/OpenRA.Mods.Common/Traits/World/EditorResourceLayer.cs b/OpenRA.Mods.Common/Traits/World/EditorResourceLayer.cs
index d9f16b6ac0..aa060ae850 100644
--- a/OpenRA.Mods.Common/Traits/World/EditorResourceLayer.cs
+++ b/OpenRA.Mods.Common/Traits/World/EditorResourceLayer.cs
@@ -28,7 +28,7 @@ namespace OpenRA.Mods.Common.Traits
 		protected static object LoadResourceTypes(MiniYaml yaml)
 		{
 			var ret = new Dictionary<string, ResourceLayerInfo.ResourceTypeInfo>();
-			var resources = yaml.Nodes.FirstOrDefault(n => n.Key == "ResourceTypes");
+			var resources = yaml.NodeWithKeyOrDefault("ResourceTypes");
 			if (resources != null)
 				foreach (var r in resources.Value.Nodes)
 					ret[r.Key] = new ResourceLayerInfo.ResourceTypeInfo(r.Value);
diff --git a/OpenRA.Mods.Common/Traits/World/Locomotor.cs b/OpenRA.Mods.Common/Traits/World/Locomotor.cs
index 2d14b273a5..53c99f2849 100644
--- a/OpenRA.Mods.Common/Traits/World/Locomotor.cs
+++ b/OpenRA.Mods.Common/Traits/World/Locomotor.cs
@@ -84,16 +84,16 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected static object LoadSpeeds(MiniYaml y)
 		{
-			var speeds = y.ToDictionary()["TerrainSpeeds"].Nodes;
+			var speeds = y.NodeWithKey("TerrainSpeeds").Value.Nodes;
 			var ret = new Dictionary<string, TerrainInfo>(speeds.Length);
 			foreach (var t in speeds)
 			{
 				var speed = FieldLoader.GetValue<int>("speed", t.Value.Value);
 				if (speed > 0)
 				{
-					var nodesDict = t.Value.ToDictionary();
-					var cost = nodesDict.TryGetValue("PathingCost", out var entry)
-						? FieldLoader.GetValue<short>("cost", entry.Value)
+					var pathingCost = t.Value.NodeWithKeyOrDefault("PathingCost");
+					var cost = pathingCost != null
+						? FieldLoader.GetValue<short>("cost", pathingCost.Value.Value)
 						: 10000 / speed;
 					ret.Add(t.Key, new TerrainInfo(speed, (short)cost));
 				}
diff --git a/OpenRA.Mods.Common/Traits/World/ResourceLayer.cs b/OpenRA.Mods.Common/Traits/World/ResourceLayer.cs
index 498eedee5f..5266eb40e3 100644
--- a/OpenRA.Mods.Common/Traits/World/ResourceLayer.cs
+++ b/OpenRA.Mods.Common/Traits/World/ResourceLayer.cs
@@ -67,7 +67,7 @@ namespace OpenRA.Mods.Common.Traits
 		protected static object LoadResourceTypes(MiniYaml yaml)
 		{
 			var ret = new Dictionary<string, ResourceTypeInfo>();
-			var resources = yaml.Nodes.FirstOrDefault(n => n.Key == "ResourceTypes");
+			var resources = yaml.NodeWithKeyOrDefault("ResourceTypes");
 			if (resources != null)
 				foreach (var r in resources.Value.Nodes)
 					ret[r.Key] = new ResourceTypeInfo(r.Value);
diff --git a/OpenRA.Mods.Common/Traits/World/ResourceRenderer.cs b/OpenRA.Mods.Common/Traits/World/ResourceRenderer.cs
index e05548a798..0a79f976b3 100644
--- a/OpenRA.Mods.Common/Traits/World/ResourceRenderer.cs
+++ b/OpenRA.Mods.Common/Traits/World/ResourceRenderer.cs
@@ -54,7 +54,7 @@ namespace OpenRA.Mods.Common.Traits
 		protected static object LoadResourceTypes(MiniYaml yaml)
 		{
 			var ret = new Dictionary<string, ResourceTypeInfo>();
-			var resources = yaml.Nodes.FirstOrDefault(n => n.Key == "ResourceTypes");
+			var resources = yaml.NodeWithKeyOrDefault("ResourceTypes");
 			if (resources != null)
 				foreach (var r in resources.Value.Nodes)
 					ret[r.Key] = new ResourceTypeInfo(r.Value);
diff --git a/OpenRA.Mods.Common/Traits/World/Selection.cs b/OpenRA.Mods.Common/Traits/World/Selection.cs
index 64e081cf1e..22c51cf905 100644
--- a/OpenRA.Mods.Common/Traits/World/Selection.cs
+++ b/OpenRA.Mods.Common/Traits/World/Selection.cs
@@ -10,7 +10,6 @@
 #endregion
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using OpenRA.Traits;
 
@@ -186,9 +185,9 @@ namespace OpenRA.Mods.Common.Traits
 			};
 		}
 
-		void IGameSaveTraitData.ResolveTraitData(Actor self, ImmutableArray<MiniYamlNode> data)
+		void IGameSaveTraitData.ResolveTraitData(Actor self, MiniYaml data)
 		{
-			var selectionNode = data.FirstOrDefault(n => n.Key == "Selection");
+			var selectionNode = data.NodeWithKeyOrDefault("Selection");
 			if (selectionNode != null)
 			{
 				var selected = FieldLoader.GetValue<uint[]>("Selection", selectionNode.Value.Value)
diff --git a/OpenRA.Mods.Common/Traits/World/SmudgeLayer.cs b/OpenRA.Mods.Common/Traits/World/SmudgeLayer.cs
index 9b830c6fe2..6ea51afb84 100644
--- a/OpenRA.Mods.Common/Traits/World/SmudgeLayer.cs
+++ b/OpenRA.Mods.Common/Traits/World/SmudgeLayer.cs
@@ -56,11 +56,11 @@ namespace OpenRA.Mods.Common.Traits
 
 		public static object LoadInitialSmudges(MiniYaml yaml)
 		{
-			var nd = yaml.ToDictionary();
 			var smudges = new Dictionary<CPos, MapSmudge>();
-			if (nd.TryGetValue("InitialSmudges", out var smudgeYaml))
+			var smudgeYaml = yaml.NodeWithKeyOrDefault("InitialSmudges");
+			if (smudgeYaml != null)
 			{
-				foreach (var node in smudgeYaml.Nodes)
+				foreach (var node in smudgeYaml.Value.Nodes)
 				{
 					try
 					{
diff --git a/OpenRA.Mods.Common/UpdateRules/Rules/20230225/ExplicitSequenceFilenames.cs b/OpenRA.Mods.Common/UpdateRules/Rules/20230225/ExplicitSequenceFilenames.cs
index 6a42628fa8..69ea3a2b64 100644
--- a/OpenRA.Mods.Common/UpdateRules/Rules/20230225/ExplicitSequenceFilenames.cs
+++ b/OpenRA.Mods.Common/UpdateRules/Rules/20230225/ExplicitSequenceFilenames.cs
@@ -230,7 +230,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 				if (!string.IsNullOrEmpty(sequenceNode.Value.Value))
 					explicitlyNamedSequences.Add(sequenceNode.Key);
 
-				var resolvedSequenceNode = resolvedImageNode.Value.Nodes.SingleOrDefault(n => n.Key == sequenceNode.Key);
+				var resolvedSequenceNode = resolvedImageNode.Value.NodeWithKeyOrDefault(sequenceNode.Key);
 				if (resolvedSequenceNode == null)
 					continue;
 
diff --git a/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs b/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs
index 76431011dc..86fc35db20 100644
--- a/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs
+++ b/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs
@@ -99,7 +99,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 
 				manualSteps.AddRange(rule.BeforeUpdate(modData));
 
-				var mapActorsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Actors");
+				var mapActorsNode = yaml.NodeWithKeyOrDefault("Actors");
 				if (mapActorsNode != null)
 				{
 					var mapActors = new YamlFileSet()
@@ -111,7 +111,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 					files.AddRange(mapActors);
 				}
 
-				var mapRulesNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Rules");
+				var mapRulesNode = yaml.NodeWithKeyOrDefault("Rules");
 				if (mapRulesNode != null)
 				{
 					if (rule is IBeforeUpdateActors before)
@@ -125,7 +125,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 					files.AddRange(mapRules);
 				}
 
-				var mapWeaponsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Weapons");
+				var mapWeaponsNode = yaml.NodeWithKeyOrDefault("Weapons");
 				if (mapWeaponsNode != null)
 				{
 					if (rule is IBeforeUpdateWeapons before)
@@ -139,7 +139,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 					files.AddRange(mapWeapons);
 				}
 
-				var mapSequencesNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Sequences");
+				var mapSequencesNode = yaml.NodeWithKeyOrDefault("Sequences");
 				if (mapSequencesNode != null)
 				{
 					if (rule is IBeforeUpdateSequences before)
@@ -216,19 +216,19 @@ namespace OpenRA.Mods.Common.UpdateRules
 						continue;
 
 					var yaml = new MiniYamlBuilder(new MiniYaml(null, MiniYaml.FromStream(mapStream, package.Name, false)));
-					var mapRulesNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Rules");
+					var mapRulesNode = yaml.NodeWithKeyOrDefault("Rules");
 					if (mapRulesNode != null)
 						foreach (var f in LoadExternalMapYaml(modData, mapRulesNode.Value, externalFilenames))
 							if (!modRules.Any(m => m.Item1 == f.Item1 && m.Item2 == f.Item2))
 								modRules.Add(f);
 
-					var mapWeaponsNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Weapons");
+					var mapWeaponsNode = yaml.NodeWithKeyOrDefault("Weapons");
 					if (mapWeaponsNode != null)
 						foreach (var f in LoadExternalMapYaml(modData, mapWeaponsNode.Value, externalFilenames))
 							if (!modWeapons.Any(m => m.Item1 == f.Item1 && m.Item2 == f.Item2))
 								modWeapons.Add(f);
 
-					var mapSequencesNode = yaml.Nodes.FirstOrDefault(n => n.Key == "Sequences");
+					var mapSequencesNode = yaml.NodeWithKeyOrDefault("Sequences");
 					if (mapSequencesNode != null)
 						foreach (var f in LoadExternalMapYaml(modData, mapSequencesNode.Value, externalFilenames))
 							if (!modSequences.Any(m => m.Item1 == f.Item1 && m.Item2 == f.Item2))
@@ -285,7 +285,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			foreach (var manualStep in transform(modData, current))
 				yield return manualStep;
 
-			var childrenNode = current.Value.Nodes.FirstOrDefault(n => n.Key == "Children");
+			var childrenNode = current.Value.NodeWithKeyOrDefault("Children");
 			if (childrenNode != null)
 				foreach (var node in childrenNode.Value.Nodes)
 					if (node.Key != null)
diff --git a/OpenRA.Mods.Common/Widgets/ControlGroupsWidget.cs b/OpenRA.Mods.Common/Widgets/ControlGroupsWidget.cs
index 17e7f82f98..c548a230e5 100644
--- a/OpenRA.Mods.Common/Widgets/ControlGroupsWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/ControlGroupsWidget.cs
@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Lint;
 using OpenRA.Traits;
@@ -47,27 +46,27 @@ namespace OpenRA.Mods.Common.Widgets
 				yield break;
 
 			var selectPrefix = "";
-			var selectPrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "SelectGroupKeyPrefix");
+			var selectPrefixNode = widgetNode.Value.NodeWithKeyOrDefault("SelectGroupKeyPrefix");
 			if (selectPrefixNode != null)
 				selectPrefix = selectPrefixNode.Value.Value;
 
 			var createPrefix = "";
-			var createPrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "CreateGroupKeyPrefix");
+			var createPrefixNode = widgetNode.Value.NodeWithKeyOrDefault("CreateGroupKeyPrefix");
 			if (createPrefixNode != null)
 				createPrefix = createPrefixNode.Value.Value;
 
 			var addToPrefix = "";
-			var addToPrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "AddToGroupKeyPrefix");
+			var addToPrefixNode = widgetNode.Value.NodeWithKeyOrDefault("AddToGroupKeyPrefix");
 			if (addToPrefixNode != null)
 				addToPrefix = addToPrefixNode.Value.Value;
 
 			var combineWithPrefix = "";
-			var combineWithPrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "CombineWithGroupKeyPrefix");
+			var combineWithPrefixNode = widgetNode.Value.NodeWithKeyOrDefault("CombineWithGroupKeyPrefix");
 			if (combineWithPrefixNode != null)
 				combineWithPrefix = combineWithPrefixNode.Value.Value;
 
 			var jumpToPrefix = "";
-			var jumpToPrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "JumpToGroupKeyPrefix");
+			var jumpToPrefixNode = widgetNode.Value.NodeWithKeyOrDefault("JumpToGroupKeyPrefix");
 			if (jumpToPrefixNode != null)
 				jumpToPrefix = jumpToPrefixNode.Value.Value;
 
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Installation/InstallFromSourceLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Installation/InstallFromSourceLogic.cs
index aabf39b7a3..e5ff34bbc4 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Installation/InstallFromSourceLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Installation/InstallFromSourceLogic.cs
@@ -246,7 +246,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				{
 					void RunSourceActions(MiniYamlNode contentPackageYaml)
 					{
-						var sourceActionListYaml = contentPackageYaml.Value.Nodes.FirstOrDefault(x => x.Key == "Actions");
+						var sourceActionListYaml = contentPackageYaml.Value.NodeWithKeyOrDefault("Actions");
 						if (sourceActionListYaml == null)
 							return;
 
@@ -263,7 +263,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 					foreach (var packageInstallationNode in modSource.Install.Where(x => x.Key == "ContentPackage"))
 					{
-						var packageName = packageInstallationNode.Value.Nodes.SingleOrDefault(x => x.Key == "Name")?.Value.Value;
+						var packageName = packageInstallationNode.Value.NodeWithKeyOrDefault("Name")?.Value.Value;
 						if (!string.IsNullOrEmpty(packageName) && selectedPackages.TryGetValue(packageName, out var required) && required)
 							RunSourceActions(packageInstallationNode);
 					}
@@ -338,9 +338,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				checkboxWidget.OnClick = () => selectedPackages[package.Identifier] = !selectedPackages[package.Identifier];
 
 				var contentPackageNode = source.Install.FirstOrDefault(x =>
-					x.Value.Nodes.FirstOrDefault(y => y.Key == "Name")?.Value.Value == package.Identifier);
+					x.Value.NodeWithKeyOrDefault("Name")?.Value.Value == package.Identifier);
 
-				var tooltipText = contentPackageNode?.Value.Nodes.FirstOrDefault(x => x.Key == nameof(ModContent.ModSource.TooltipText))?.Value.Value;
+				var tooltipText = contentPackageNode?.Value.NodeWithKeyOrDefault(nameof(ModContent.ModSource.TooltipText))?.Value.Value;
 				var tooltipIcon = containerWidget.Get<ImageWidget>("PACKAGE_INFO");
 				tooltipIcon.IsVisible = () => !string.IsNullOrWhiteSpace(tooltipText);
 				tooltipIcon.GetTooltipText = () => tooltipText;
diff --git a/OpenRA.Mods.Common/Widgets/Logic/ServerListLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/ServerListLogic.cs
index 445791c800..18581affab 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/ServerListLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/ServerListLogic.cs
@@ -487,7 +487,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 							continue;
 
 						var game = new MiniYamlBuilder(MiniYaml.FromString(bl.Data)[0].Value);
-						var idNode = game.Nodes.FirstOrDefault(n => n.Key == "Id");
+						var idNode = game.NodeWithKeyOrDefault("Id");
 
 						// Skip beacons created by this instance and replace Id by expected int value
 						if (idNode != null && idNode.Value.Value != Platform.SessionGUID.ToString())
@@ -495,7 +495,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 							idNode.Value.Value = "-1";
 
 							// Rewrite the server address with the correct IP
-							var addressNode = game.Nodes.FirstOrDefault(n => n.Key == "Address");
+							var addressNode = game.NodeWithKeyOrDefault("Address");
 							if (addressNode != null)
 								addressNode.Value.Value = bl.Address.ToString().Split(':')[0] + ":" + addressNode.Value.Value.Split(':')[1];
 
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Settings/HotkeysSettingsLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Settings/HotkeysSettingsLogic.cs
index 561f8f991e..154fd98546 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Settings/HotkeysSettingsLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Settings/HotkeysSettingsLogic.cs
@@ -138,7 +138,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				foreach (var hg in hotkeyGroupsYaml.Nodes)
 				{
-					var typesNode = hg.Value.Nodes.FirstOrDefault(n => n.Key == "Types");
+					var typesNode = hg.Value.NodeWithKeyOrDefault("Types");
 					if (typesNode != null)
 						hotkeyGroups.Add(hg.Key, FieldLoader.GetValue<HashSet<string>>("Types", typesNode.Value.Value));
 				}
diff --git a/OpenRA.Mods.Common/Widgets/ProductionPaletteWidget.cs b/OpenRA.Mods.Common/Widgets/ProductionPaletteWidget.cs
index 66edfbd2b2..d63a3af8bb 100644
--- a/OpenRA.Mods.Common/Widgets/ProductionPaletteWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/ProductionPaletteWidget.cs
@@ -132,12 +132,12 @@ namespace OpenRA.Mods.Common.Widgets
 		public static IEnumerable<string> LinterHotkeyNames(MiniYamlNode widgetNode, Action<string> emitError)
 		{
 			var prefix = "";
-			var prefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "HotkeyPrefix");
+			var prefixNode = widgetNode.Value.NodeWithKeyOrDefault("HotkeyPrefix");
 			if (prefixNode != null)
 				prefix = prefixNode.Value.Value;
 
 			var count = 0;
-			var countNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "HotkeyCount");
+			var countNode = widgetNode.Value.NodeWithKeyOrDefault("HotkeyCount");
 			if (countNode != null)
 				count = FieldLoader.GetValue<int>("HotkeyCount", countNode.Value.Value);
 
diff --git a/OpenRA.Mods.Common/Widgets/SupportPowersWidget.cs b/OpenRA.Mods.Common/Widgets/SupportPowersWidget.cs
index f44c1869dd..2dc70f7364 100644
--- a/OpenRA.Mods.Common/Widgets/SupportPowersWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/SupportPowersWidget.cs
@@ -70,12 +70,12 @@ namespace OpenRA.Mods.Common.Widgets
 		public static IEnumerable<string> LinterHotkeyNames(MiniYamlNode widgetNode, Action<string> emitError)
 		{
 			var prefix = "";
-			var prefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "HotkeyPrefix");
+			var prefixNode = widgetNode.Value.NodeWithKeyOrDefault("HotkeyPrefix");
 			if (prefixNode != null)
 				prefix = prefixNode.Value.Value;
 
 			var count = 0;
-			var countNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "HotkeyCount");
+			var countNode = widgetNode.Value.NodeWithKeyOrDefault("HotkeyCount");
 			if (countNode != null)
 				count = FieldLoader.GetValue<int>("HotkeyCount", countNode.Value.Value);
 
diff --git a/OpenRA.Mods.Common/Widgets/ViewportControllerWidget.cs b/OpenRA.Mods.Common/Widgets/ViewportControllerWidget.cs
index 7da08b1fb2..61b184d80d 100644
--- a/OpenRA.Mods.Common/Widgets/ViewportControllerWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/ViewportControllerWidget.cs
@@ -105,17 +105,17 @@ namespace OpenRA.Mods.Common.Widgets
 		public static IEnumerable<string> LinterHotkeyNames(MiniYamlNode widgetNode, Action<string> emitError)
 		{
 			var savePrefix = "";
-			var savePrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "BookmarkSaveKeyPrefix");
+			var savePrefixNode = widgetNode.Value.NodeWithKeyOrDefault("BookmarkSaveKeyPrefix");
 			if (savePrefixNode != null)
 				savePrefix = savePrefixNode.Value.Value;
 
 			var restorePrefix = "";
-			var restorePrefixNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "BookmarkRestoreKeyPrefix");
+			var restorePrefixNode = widgetNode.Value.NodeWithKeyOrDefault("BookmarkRestoreKeyPrefix");
 			if (restorePrefixNode != null)
 				restorePrefix = restorePrefixNode.Value.Value;
 
 			var count = 0;
-			var countNode = widgetNode.Value.Nodes.FirstOrDefault(n => n.Key == "BookmarkKeyCount");
+			var countNode = widgetNode.Value.NodeWithKeyOrDefault("BookmarkKeyCount");
 			if (countNode != null)
 				count = FieldLoader.GetValue<int>("BookmarkKeyCount", countNode.Value.Value);
 
diff --git a/OpenRA.Mods.D2k/UtilityCommands/D2kMapImporter.cs b/OpenRA.Mods.D2k/UtilityCommands/D2kMapImporter.cs
index 462b733880..70d19fdbd2 100644
--- a/OpenRA.Mods.D2k/UtilityCommands/D2kMapImporter.cs
+++ b/OpenRA.Mods.D2k/UtilityCommands/D2kMapImporter.cs
@@ -384,7 +384,7 @@ namespace OpenRA.Mods.D2k.UtilityCommands
 						actorNodes.Add(new MiniYamlNode("Actor" + (map.ActorDefinitions.Count + actorNodes.Count), a.Save()));
 
 						if (map.PlayerDefinitions.Concat(playerNodes).All(
-							x => x.Value.Nodes.Single(y => y.Key == "Name").Value.Value != kvp.Owner))
+							x => x.Value.NodeWithKey("Name").Value.Value != kvp.Owner))
 						{
 							var playerInfo = PlayerReferenceDataByPlayerName[kvp.Owner];
 							var playerReference = new PlayerReference
diff --git a/OpenRA.Test/OpenRA.Game/MiniYamlTest.cs b/OpenRA.Test/OpenRA.Game/MiniYamlTest.cs
index c9b223b276..4223eca9cc 100644
--- a/OpenRA.Test/OpenRA.Game/MiniYamlTest.cs
+++ b/OpenRA.Test/OpenRA.Game/MiniYamlTest.cs
@@ -247,7 +247,7 @@ Test:
 				 .First(n => n.Key == "Test").Value.Nodes;
 
 			Assert.IsTrue(result.Any(n => n.Key == "MockString"), "Node should have the MockString child, but does not.");
-			Assert.IsTrue(result.First(n => n.Key == "MockString").Value.ToDictionary()["AString"].Value == "Override",
+			Assert.IsTrue(result.First(n => n.Key == "MockString").Value.NodeWithKey("AString").Value.Value == "Override",
 				"MockString value has not been set with the correct override value for AString.");
 		}
 
@@ -272,7 +272,7 @@ Test:
 				.First(n => n.Key == "Test").Value.Nodes;
 
 			Assert.IsTrue(result.Any(n => n.Key == "MockString"), "Node should have the MockString child, but does not.");
-			Assert.IsTrue(result.First(n => n.Key == "MockString").Value.ToDictionary()["AString"].Value == "Override",
+			Assert.IsTrue(result.First(n => n.Key == "MockString").Value.NodeWithKey("AString").Value.Value == "Override",
 				"MockString value has not been set with the correct override value for AString.");
 		}
 
diff --git a/mods/ts/sequences/civilian.yaml b/mods/ts/sequences/civilian.yaml
index 8e5aaa9cd5..d6903b3f0a 100644
--- a/mods/ts/sequences/civilian.yaml
+++ b/mods/ts/sequences/civilian.yaml
@@ -779,7 +779,6 @@ ctdam:
 	damaged-idle-water-b:
 		Filename: ctdam_b.shp
 		Start: 24
-		Start: 8
 		Length: 8
 		Tick: 200
 
diff --git a/mods/ts/sequences/structures.yaml b/mods/ts/sequences/structures.yaml
index acc008a3c8..3cd244ed7f 100644
--- a/mods/ts/sequences/structures.yaml
+++ b/mods/ts/sequences/structures.yaml
@@ -1667,7 +1667,6 @@ napuls.nod:
 		ZOffset: 512
 		BlendMode: Additive
 		IgnoreWorldTint: True
-		IgnoreWorldTint: True
 		DepthSprite:
 	icon:
 		Filename: sidebar-nod|empicon.shp