Some of my favorite command line tools display some sort of quick help at the bottom of the screen:

nano

htop

I feel that mitmproxy would greatly benefit from some more discoverability as well. The help menu lists a long list of keybindings, many of which just aren't too relevant when you are starting out. How would you all feel about adding a help bar similar to htop/nano? In particular, we could make that view-dependent, so that you get meaningful key shortcut help in flows and options editor as well 😃

Maybe someone wants to come up with a first prototype? Implementation should't be too hard. You need to get some familiarity with urwid, and then it's probably enough to wrap the footer here in an urwid.Pile which also displays the quick help.
I'm happy to help if you get stuck somewhere!