[tannhaeuser]

Maybe I'm misunderstanding, but Apache httpd has performed URL rewriting such as adding a .html suffix after mapping URLs to file names where appropriate, and other transformations such as content negotiation for languages, spelling correction, etc. for ages.

[untitaker_]

Cloudflare automatically redirects any /foo.html URL to /foo, with a permanent redirect. That is certainly not standard behavior, neither on httpd nor gh pages