Lexicon: defs#source (knownValues), identifiers[] on movie/tvShow/episode items and list items, originSource, releaseYear, absoluteNumber; season/episode numbers of an episode item are optional. C#: IdentifiedRecord base (primary id, lookup by any identifier, unknown sources and fields survive a rewrite); migrations keep the other identifiers; import_to_pds writes the new shape. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>