Ctrl + / opens the list of shortcuts.
…but if you press it again, it doesn’t close the pop up. If it did, that would be lovely. 
Note: I know you can press Esc, but the UX would be clearer for new users if it were a show/hide toggle (IMO).
I’m finding it useful when training my team and clients to use shortcuts to remind them of the “one shortcut to rule them all” —> Ctrl - /
Thanks for sharing this feedback with us @DaveJMason! Not sure when we’ll be able to look into this, but I’ll make sure to keep you posted on this thread as soon as I hear anything internally!
Have a great day 