You are browsing a read-only backup copy of Wikitech. The live site can be found at wikitech.wikimedia.org
To export the enwp-boxes 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:
You must have appropriate permissions on destination wiki (including the right to edit system messages) and import from file uploads must be enabled.