Gadget export
To export the mmgkc-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:
* mmgkc-core[ResourceLoader|type=general|dependencies=oojs-ui-core,oojs-ui-widgets|hidden|targets=desktop,mobile]|mmgkc-core.js|mmgkc.css
You must have appropriate permissions on destination wiki (including the right to edit system messages) and import from file uploads must be enabled.