Compost 3.x has done away with the former "Composition" system to make use of a vanilla feature, loot tables!

You may find the the compost loot table under /data/compost/loot_table/composters/compost.json. The compost loot table may be overwritten with a data pack to be customized.

The composter's loot table supports the vanilla minecraft:origin parameter. Any modded condition that uses this parameter can also work with Compost!

As well, Compost's own compost:compostables parameter offers the exclusive ability to generate compost based on the compostables added. This parameter is a list of ItemStacks that is fed all of the compostables added to the composter.

In the loot table, the compost:match_compostable condition runs a check to see if one of the configured items is in the compost:compostables parameter. This takes in an item predicate, so it supports using tags as well as plain items!