Gadget export
To export the Twinkle 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:
* Twinkle [ResourceLoader |dependencies=ext.gadget.morebits, ext.gadget.select2, mediawiki.api, mediawiki.language |rights=autoconfirmed |type=general |peers=Twinkle-pagestyles |requiresES6] |TwinkleV3.js |TwinkleV3.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.