I know there are already several - separate - wishes about this for years, but this is one area that could easily improve usability of tabs.

Whenever using MB's tabs, I miss those three menu items of Chrome or any other web browsers.
Especially if you're using several locked tabs, the main panel gets easily filled up with numerous opened tabs, and having to close them one by one is not really something expected for many users who get used to those "standard" browser tab menus.
Also undo menu will save the user from navigating again to a deep-nested folder or re-creating a complex search results.