As a regular KiCad user, I always point out the power of the hotkeys. Specifically I always pointed out that hitting the ‘?’ key brings up a menu to LEARN the hotkeys, which is the best way to do it, IMO.
Well guess what? Discourse has the same thing!
Want to become a wiz of reading through threads on here? Hit the ‘?’ button to learn how to navigate sans mouse and much faster overall.
I know slightly off topic. (As this only answers the first part of your post.)
This is no longer true for KiCad version 5 (and especially for KiCad version 5.1)
This version now has its shortcuts configurable. Which might have broken this static dialog. To view (or edit) hotkeys in these versions go to the hotkey editor which is found in some dialog of the preferences menu (depending on your exact KiCad version)
In current KiCad nightly (will become KiCad 5.1) it is under preferences -> preferences (select hotkeys in the tree view)
That’s a pretty horrible default on macOS as on my machine it causes my monitor to go from extending my desktop to mirroring my desktop. I had to change it back to ? I’m not sure why they changed it from ? in the first place, but I know this isn’t the KiCad forums.