To export the Shortdesc-helper-loader 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:
* Shortdesc-helper-loader[ResourceLoader|dependencies=mediawiki.api,mediawiki.notify,user.options,mediawiki.util|skins=citizen,vector,monobook,modern,timeless|peers=Shortdesc-helper-pagestyles-vector]|Shortdesc-helper.js
You must have appropriate permissions on the destination wiki (including the right to edit system messages) and import from file uploads must be enabled.