Any updates on this? Really looking forward to using a "more modular" Foundation. Losing libcurl dependency on Linux would be great, but also thinking of possible use of Foundation when WebAssembly target starts working. I doubt it would make sense to bundle SwiftNIO in WebAssembly builds of Foundation. URLSession would probably need to bridge to browser's implementation of fetch on JavaScript side.
Either way "more modular" Foundation would unblock a lot of things for many platforms.