I believe they are actually emacs bindings. These bindings originates in emacs and were then used by readline. Software that uses readline then acquires these bindings, including bash, etc. So I wouldn't say that these are standard shell bindings that happen to be used by emacs, since they originated in emacs and shells happen to use them.

Thanks. I've been living a lie for years. :)

Emacs had them first; shells copied them.