Are these proposals "a la carte" or does each accepted proposal make the basic WebAssembly spec bigger? Like if the GC proposal is accepted, does every WebAsse

Are these proposals "a la carte" or does each accepted proposal make the basic WebAssembly spec bigger? Like if the GC proposal is accepted, does every WebAssembly implementation now need to support GC all the time? Or can a slimmed-down version of WebAssembly still load modules that don't use GC?