What does a butcher villager do in Minecraft?

Butchers trade meat and stews. Their job site block is the Smoker. 14 raw chicken for 1 emerald - a cooked chicken farm doubles as an emerald source.

What workstation does a butcher need?

A Smoker. Place it next to an unemployed villager and it becomes a butcher. Breaking the block before any trade resets the villager's trades.

Workstation: Smoker Java Bedrock

Butchers trade meat and stews. Their job site block is the Smoker.

14 raw chicken for 1 emerald - a cooked chicken farm doubles as an emerald source
Cheap cooked food (8 chicken or 5 porkchops per emerald) for long mining trips
Buys dried kelp blocks at expert: kelp farms print emeralds

Villager wants	You get	In stock	Chance offered
14 x Raw Chicken	Emerald	16	50% JE / 33% BE
4 x Raw Rabbit	Emerald	16	50% JE / 33% BE
7 x Raw Porkchop	Emerald	16	50% JE / 33% BE
Emerald	Rabbit Stew	12	50% JE / 100% BE

Villager wants	You get	In stock	Chance offered
15 x Coal	Emerald	16	67% JE / 100% BE
Emerald	8 x Cooked Chicken	16	67% JE / 50% BE
Emerald	5 x Cooked Porkchop	16	67% JE / 50% BE

Villager wants	You get	In stock	Chance offered
10 x Raw Beef	Emerald	16	100% JE / 50% BE
7 x Raw Mutton	Emerald	16	100% JE / 50% BE

Villager wants	You get	In stock	Chance offered
10 x Dried Kelp Block	Emerald	12	100%

Villager wants	You get	In stock	Chance offered
10 x Sweet Berries	Emerald	12	100%

All butcher trades are guaranteed in Bedrock; in Java several are chance-based picks.