These kinds of shortcuts are part of Apple software as a whole, and apparently have been a thing since at least OSX. These behaviors were supposed to be covered in the documentation, but I don't know how true this is nowadays.
Special mention to all text input fields in macOS having Emacs-style shortcuts.
It goes back further than that. I remember being able to buy key-combo cheat cards for System 7, and I have no reason to think the shortcuts they covered wouldn't also have been present in System 6.
Special mention to all text input fields in macOS having Emacs-style shortcuts.