**Relevant wish: [[ https://meta.wikimedia.org/wiki/Community_Wishlist/W215 | W215: Open the Wikimedia Commons file page directly ]]**
See the wish for more detailed info. Per the [[ https://meta.wikimedia.org/w/index.php?title=Talk:Community_Wishlist/W215&oldid=30010177#Why | talk page ]], it seems linking to the local description is a remnant from way back before we had #mediawiki-extensions-centralauth and #globalusage. Today, we should be safe to always link to Commons when a local override doesn't exist. This will help drive traffic to Commons, centralize File maintenance, and be less confusing for newer users who are trying to edit the preexisting description.
Since the file description link is generated during parsing, we need to patch both Core's `MediaTransformOutput` as well as Parsoid.