Google's cache implementation is documented (https://github.com/ampproject/amphtml/blob/master/spec/amp-cache-guidelines.md https://github.com/ampproject/amphtm

Google's cache implementation is documented (https://github.com/ampproject/amphtml/blob/master/spec/amp-cache-guidelines.md https://github.com/ampproject/amphtml/blob/master/spec/amp-c... and a few more files in that dir) but not itself open source. Cloudflare also offers an AMP cache if you'd rather not use Google's.