

~/.local/share/Steam/SteamApps/sourcemods./Users/Username/Library/Application Support/Steam/SteamApps/sourcemods.Example: Program Files/Steam/SteamApps/sourcemods/modname. Program Files/Steam/SteamApps/sourcemods.

You will need to have run a Source Engine game or the SDK at least once for the directory to appear.

Because of that, HL2MMod relies on the Half-Life 2 games, which are installed on your system. Half-life 2: MMod is primarily a gunplay enhancement mod for all current Half-Life 2 games and Steam Store redistributed Half-Life 2 Mods ( every mod needs “compatibility patch” ).
