OpenRA/OpenRA.Game/Properties/launchSettings.json

{
  "profiles": {
    "Tiberian Dawn": {
      "commandName": "Project",
      "commandLineArgs": "Game.Mod=cnc"
    },
    "Red Alert": {
      "commandName": "Project",
      "commandLineArgs": "Game.Mod=ra"
    },
    "Dune 2000": {
      "commandName": "Project",
      "commandLineArgs": "Game.Mod=d2k"
    },
    "Tiberian Sun": {
      "commandName": "Project",
      "commandLineArgs": "Game.Mod=ts"
    }
  }
}