Between Google's browser market share and Cloudflare's internet dominance, I'm getting quite worried about the speed at which large changes like this are occurring. Google rolls out an experimental feature with no standardization in Chrome and here it's already supported by Cloudflare and in the wild.
Web Packaging in the W3C draft was a completely different idea - there's not even a single mention of signatures. The "specification" you linked is actually a standards draft published by Google. And the open source project is again, another Google project that only benefits their AMP ecosystem.
