A CMI Extension by The456gamer

set per-shulkerbox overrides cmi backpacks
prevent access to some shulkers as backpacks, make others cheaper / free / more expensive
stored in nbt, and kept even after it is placed down / broken

• modern cmi (tested and compiled with CMI-9.6.0.9.jar, CMILib1.3.1.1.jar)
• minecraft 1.20.1
• latest paper (tested on Paper version git-Paper-63 (MC: 1.20.1) (Implementing API version 1.20.1-R0.1-SNAPSHOT) (Git: c0936a7))

restrictedbackshulkers.command.execute is needed for all commands,
to "know its existance", otherwise it will say command not found and not tabcomplete

view current cost / opening
requires restrictedbackshulkers.command.execute and restrictedbackshulkers.command.view

set new cost / opening of the item in your hand requires restrictedbackshulkers.command.execute and restrictedbackshulkers.command.set
if $cost is less than 0, opening will be fully prevented
if $cost is exactly 0, opening will be free
otherwise, $cost will be charged on opening the shulkerbox as a backpack

reset to default (in cmi config) of the item in your hand
requires restrictedbackshulkers.command.execute and restrictedbackshulkers.command.set
it will remove any custom cost / restrictions