copyright.html is currently specific to the Wikidata Query Service. It specifies Wikidata, its license and other things that do not apply to other installations. This should somehow be configurable without changing the revision-controlled file.
GIVEN a 3rd party Wikibase installations
AND different licensing conditions of that installation
THEN it should be possible to change the licensing text without touching a file under revision control
- a 3rd party installation can easily change the licensing information to fit their project