Incoming redirects act as alias-IDs for entities. They should be available in the entity's JSON representation, at least in some cases:

• internal (DB): no
• API output: optional (T98317)
• JSON dumps: not in entity, but as separate non-entity entries (T98320)
• EntityData: always (or at least per default) (T98322)

Caveat: Structural inconsistency between dumps and EntityData. For JSON dumps, it's more sensible (and performant) to have redirects as separate entries, while for EntityData, we don't really have a place outside the entity itself where we could put the redirect info.