The "What's New" for Firefox 112.0 mentions that the shortcut key to un-close a tab is (Cmd/Ctrl)-Shift-T. I didn't know that! I wish that was shown on the menus that display on right-clicking on a tab. Shortcut keys are shown on the regular menu (which shows up on pressing Alt), and also in the tooltips for icons, such as the "back" icon. The shortcut keys are also not shown on the context menu of a page (that displays on right-clicking in the middle of a page).
I use Blender for animations. That open-source program does show shortcut keys on tabs and in the work area. Having the shortcut key reminders present helps me be more efficient using software.
Chris