Gadget export
To export the wikisync-core gadget, click on "Download" button, save the downloaded file, go to Special:Import on destination wiki and upload it. Then add the following to MediaWiki:Gadgets-definition page:
* wikisync-core[ResourceLoader|targets=desktop,mobile|dependencies=ext.gadget.rsw-util,oojs-ui-core,oojs-ui-widgets,oojs-ui-windows|hidden|type=general]|wikisync-core.js|wikisync-core.css
You must have appropriate permissions on destination wiki (including the right to edit system messages) and import from file uploads must be enabled.