Alt as a shortcut to show a hidden menu bar

Firefox as a nice default, it has the menu bar hidden and you can show and activate the menu bar pressing Alt.

I think this is a better shortcut than Ctrl+M.

Personally that droveme crazy in Firefox, since every time I hit alt for something else or even by accident, the menubar showed and re-arranged the contents of the window. I disabled the behavior and lowered my blood pressure!

True. Try Alt with no tabs when only one and autohidden bookmarks css. It’s a bit more than blood pressure.