Gadget export
To export the dropdown-menus gadget, click on "Download" button, save the downloaded file, go to Special:Import on the destination wiki and upload it. Then add the following to MediaWiki:Gadgets-definition page:
* dropdown-menus [ResourceLoader |dependencies=mediawiki.api, mediawiki.util, mediawiki.Title, user.options |peers=dropdown-menus-pagestyles |skins=vector, vector-2022, monobook, timeless, modern, cologneblue] |MoreMenu.enwiki.js |dropdown-menus.js
You must have appropriate permissions on the destination wiki (including the right to edit system messages) and import from file uploads must be enabled.