Testing a map in the game

Tools ▸ Test Map needs the installed game rather than its data. Neither version of StarCraft opens a map handed to it from outside, so the editor writes the map into a scmJS folder under the game's Maps folder, where Single Player ▸ Custom Game lists it. The desktop app finds the installation in the same places the archive search looks, takes a folder you pick and remembers it, and starts the game: the executable itself on Windows, open -a on macOS, Wine elsewhere. A browser has no such reach. Chrome and Edge write into a folder you pick once and remember; other browsers download the file.