Please note that loot boxes can also be made in-game using the config menu.

All loot boxes go in the config/progressiveboxes/boxes folder. Create a new file in this folder and make sure the name ends with .json (for example: weaponsbox.json)

The json is a BoxData object.

All mob groups go in the config/progressiveboxes/mobgroups folder. Create a new file in this folder and make sure the name ends with .json (for example: greenanimals.json)

The json is a MobGroup object.