Gadget export
To export the mobile-sidebar 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:
* mobile-sidebar [ResourceLoader |skins=vector, vector-2022] |mobile-sidebar.js |mobile-sidebar.css
You must have appropriate permissions on the destination wiki (including the right to edit system messages) and import from file uploads must be enabled.