First of all this method clearly working on github, for example pages showing done:
https://github.com/account
https://github.com/inbox
There is no .php extension at all + not needed ?page=account or ?page=inbox
In my opinion it’s done via .htaccess.
Maybe someone knows how it should look in order to archieve same effect like github site ?
This can be achieved using mod_rewrite for apache
You put a .htaccess file in your document root and give it rules (Regular Expressions) to match the called URLs with
It looks similar to this:
There are several tutorials regarding mod_rewrite on the internet