Gadget export
To export the XFDcloser-core 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:
* XFDcloser-core[ResourceLoader|dependencies=mediawiki.util,mediawiki.api,mediawiki.Title,oojs-ui-core,oojs-ui-widgets,oojs-ui-windows,jquery.ui,ext.gadget.libExtraUtil,ext.gadget.morebits|hidden|type=general]|XFDcloser-core.js|XFDcloser.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.