Include current app shortcuts?

Apps like Files have a lot of useful, but hard to discover shortcuts. In some cases we could add shortcuts to tooltips or menu's but shortcuts like alt+up, for navigating to the parent folder, doesn't even have a button.

Could we extend this overlay to include a list of app shortcuts? It's probably not scalable to show this for all apps, but maybe we can list just the shortcuts for the current app. (Beside the system wide shortcuts) The current app being the app that had focus before the shortcut overlay was opened.
This way we re-use a known shortcuts screen and we don't have to add extra interface (help screens) in each app.

One of the challenges is probably to have apps make their shortcuts available to the shortcuts overlay?