How 'experimental' is experimental-mv?

Clang supports multi-value WASM from C via the experimental flag ‘experimental-mv’ (among other flags). Far as I can tell, compiling C using Clang is the only working way to produce this code from any high-level language. (Rust doesn’t work; AssemblyScript has yet to implement it; etc)

How do experimental flags in Clang pass the experimental stage? Is there a chance that the flag could lose support in the future?

As multi-values are now part of the core WebAssembly specification, it’s hard to imagine the flag being dropped altogether. The direction of travel would be towards no longer marking it “experimental”, though I don’t think there’s very active work on this currently.