It appears that the way NixOS installs steamtinkerlaunch causes a part of the script (the part that tries to delete the language file to replace it) causes the entire program to break down, meaning the package is effectively useless.
It appears that the way NixOS installs steamtinkerlaunch causes a part of the script (the part that tries to delete the language file to replace it) causes the entire program to break down, meaning the package is effectively useless.