I do think there is a big difference between "a subset of JavaScript" and "a bunch of JavaScript APIs" from a standardization point of view. All engines have been implementing special optimizations for JavaScript subsets ever since the JS performance wars started. Nobody thinks we need to standardize polymorphic inline caches, for example, even though the set of JS code that is PIC-friendly is different from the set of JS code that is heavily polymorphic (and this distinction would be easy to describe formally if anyone cared to). asm.js is just an optimization writ large: the reason why it's not a protocol is that any conforming JavaScript implementation is also an asm.js implementation.

I think people are reading a lot more into my posts than was intended. I'm not calling out QUIC specifically, since I'm not involved with the details of its standardization anyway. The point is simply that open source doesn't automatically mean non-proprietary.