So I wanted to make old crystal plant edible but when i changed .item to .consumable in the mod folder it crashed the game. Probably because in reuglar game assets its .item . How can I make item already in game to be edible? Thanks. Sorry for bad English.
Well you really can't change the file extension of a vanilla asset via modding. You'd have to actually unpack everything, rename it, and repack the assets thus replacing vanilla's packed.pak file. This is totally non-viable if you wanted to distribute a mod, and not recommended anyhow. Your error comes from there now being 2 files that identify as the same thing aka duplicate ID. Instead make a new .consumable item with a different ID. Make a .recipe to turn the regular item into the consumable item (presumably by cooking it).
Id say your best bet, is to patch the normal .item file and change the item name to something like "itemName" : "REMOVEDcrystalplant" This will keep the game from finding it when it gets referenced. Now, you create your own consumable file, and name it "itemName" : "crystalplant" Now, everytime the game looks for crystalplant, it will find your consumable and not the removed item