Villager biome types are not controlled by tags

The biome outfit a villager spawns with is not controlled by tags. This is inconsistent with other mobs. Other biome-dependent variants of mobs use tags to control what biomes a variant spawns in:
#minecraft:spawns_cold_variant_frogs
#minecraft:spawns_gold_rabbits
#minecraft:spawns_snow_foxes
#minecraft:spawns_warm_variant_frogs
#minecraft:spawns_white_rabbits