Two usages are left:
- ChangeOpStatement. We tried multiple times to get rid of this, see for example https://github.com/wmde/WikibaseDataModel/pull/479. The relevant ticket for this "add statement at index" feature is T98375: [Task] ChangeOpClaim should handle indices per property id.
- EntityChangeFactory. That's a hack, see T113468: [Task] Use compact representation of diffs in EntityChange.
Patches for review: