Since we’re already going to make a breaking change to the wbcheckconstraints API, we could also consider removing the claimid parameter, which is also kind of tied to the now-obsolete idea of only checking constraints on statements:

1. Once we check qualifiers and references, its semantics become a bit unclear: should it check only the main snak or all snaks of the statement?
2. It’s no longer a full “address to anything that constraints can be checked on”, because it doesn’t support selecting a single qualifier or reference snak to check constraints on.

I suspect that no one currently uses that parameter, but @Ladsgroup is running a query on the ApiAction dataset to verify this.

If it turns out people need a way to request constraint checks at sub-entity granularity, we should come up with something better than claimid.