Quoted from here: https://www.ampproject.org/docs/get_started/about-amp.html
AMP is a way to build web pages for static content that render fast. AM
For a text example with http:
http://example.com/blog/index.html
Cache URL is:
https://example-com.cdn.ampproject.org/c/example.com/blog/index.html
With https:
https://example.com/blog/index.html
Cache URL is (notice the /s/):
https://example-com.cdn.ampproject.org/c/s/example.com/blog/index.html
For an image, replace the /c/ with /i/, for example,
http://example.com/blog/picture.jpeg
Cache URL is:
https://example-com.cdn.ampproject.org/i/s/example.com/blog/picture.jpeg
More details on cache URL name construction and name construction tools can be found here: https://developers.google.com/amp/cache/overview