SUBSET-matching, not Extract: a grouped pair's arm carries a literal
UNION on the discriminator ({ ecosystem: 'SD1' | 'SDXL' | ... }), which
Extract by a single literal would drop. An arm matches when any of the
requested literals is one of the arm's.
SUBSET-matching, not
Extract: a grouped pair's arm carries a literal UNION on the discriminator ({ ecosystem: 'SD1' | 'SDXL' | ... }), whichExtractby a single literal would drop. An arm matches when any of the requested literals is one of the arm's.