The reference to the 'wikidata-shortcopyrightwarning' message in the wikibase software introduced in Ie7dba11 should be removed.
As I understand, for doing this without breaking wikidata, the proper steps would be to:
- Move (first copy, later delete in step 3) all the messages (subpages) on wikidata.org:
- Merge and deploy I7d7d8a9
- Delete https://www.wikidata.org/wiki/MediaWiki:Wikidata-shortcopyrightwarning and its subpages