This is a spime trophy system with its own inventory, dedicated only to trophies.
The mod does not include the trophies themselves.
Custom trophies can be added by modifying the config file "packName\config\TrophyList.toml" after running the game once with the mod installed.
The GUI works the same way as an inventor; when you hover over an item, you can see its name and lore, but you can't move or add items in the GUI.
You can reward the player by using the command /addTrophy trophy_nick_name playerNameOrSelector
You can also remove all the trophies from the player by using the command /clearTrophies playerNameOrSelector