WebGPU is not a browser API. It is a lower level API with official, supported implementations in C++ and Rust with zero browser dependencies. See for example:

https://dawn.googlesource.com/dawn

https://eliemichel.github.io/LearnWebGPU/

Yes it is exposed to Javascript applications by browsers that support it, much like WebGL exposes OpenGL ES. But that’s a separate thing.