Summary:
Breaking a campfire by hand or pickaxe returns 2 coal to the player, however a campfire is mostly crafted out of wood and should return 2 charcoal (as it is currently working on the java edition snapshots, tested 19w06a).

Steps to reproduce:

• Place a campfire with experimental gamplay enabled
• Break a campfire by hand or by pickaxe (survival)
• Look at the drops

Expected behavior:
The campfire to drop 2 charcoal when broken.

Observed behavior:
The campfire drops 2 coal when broken.