Gadget export
To export the ReferenceTooltips 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:
* ReferenceTooltips [ResourceLoader |default |skins=vector, vector-2022, monobook, timeless, modern, cologneblue |type=general |dependencies=mediawiki.cookie, jquery.client] |ReferenceTooltips.js |ReferenceTooltips.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.