Before adding a new gadget, please evaluate whether it might be smarter to add this functionality by integrating into an existing gadget like MediaWiki:Gadget-ExtraTabs2.js.
You are responsible for the gadgets, you add! If you decide to quit the project, please ask for a maintainer before. If there is no voluntary maintainer, remove the gadget from this list. Gadgets without enough amount of maintenance often suffer from security issues and unexpected behavior.