Wow this is pure gold. I cannot understand why I have never run across this until now. Thank you for pointing this out!
I also found editing you command and search history in vim by accident.
:q will quit the editor.
q: will open a buffer with a history of your vim commands, which are navigable and editable. Edit a command, then enter and it's executed.
In command history edit mode, :q to exit that mode.
q/ works for searches.