Google doesn't run in mainland china, so this is a bit of a strange question. But let's assume that Google did. How would AMP or signed exchanges change the accessibility of Taiwan related content on Google in mainland china? Are you saying that the current Google results page would show Taiwan related content, but signed exchanges wouldn't, or what?

> Is it like VPN/Proxy or has more knobs?

Neither. It's literally a way to say "a site had this html, css, and js, and cryptographically signed the blob so that we can re-host it and you can be certain that the person re-hosting hasn't modified it in any way."