I did only briefly look at the proposal. What did you find so ugly?

I misread the proposal. Thought it was for JSDoc.

Misread no, you didn't read.

Specifically, you saw the section titled "Limits of JSDoc Type Annotations"?

Specifically, I saw JSDoc syntax and it triggered me so much that I closed the page and threw my phone away in disgust at absurdness of even the idea that someone thought having something like this unironically is a remotely good idea.

I support this behavior as the only correct reaction.

What do you mean ugly? This basically is making Typescript official.

They just can't have browsers doing the actual type checking because there isn't a specification for how to do that, and writing one would be extremely complicated, and I'm not sure what the point would be anyway.

I misread the proposal, tho it it was for JSDoc.

There is no language spec for TS. No alternative implementations. All we have is checker.ts. It's ugly and slow.