JSON Files goes to:
data/corewithstuff/tags/items/
thermal_immune.json, radiation_immune.json, acid_immune.json, fall_damage_immune.json, provides_oxygen.jsonthermal_immune_singular.json, radiation_immune_singular.json, acid_immune_singular.json, fall_damage_immune_singular.json, provides_oxygen_singular.jsonTo enable support only when a complete four-piece suit is worn, use the assigned json name. Players can mix and match any items listed in the values, provided all four armor slots (helmet, chestplate, leggings, and boots) are filled with items from this list. For Example: Wearing a Diamond Helmet and Leggings with Leather Chestplate and Boots will function if all those pieces are registered.
If you want a single piece of equipment (such as a specific helmet or a ring) to provide oxygen support without requiring a full suit, use the “jsonname_singular” registry.