Name of the mod:  ShulkerBoxTooltip

Url about it:  https://www.curseforge.com/minecraft/mc-mods/shulkerboxtooltip

Why do you think it should be allowed:

It's a quality of life mod, it helps you to see inside the shulker boxes that are in the inventory to see the items in it.
It helps when you are in a place in spawn you can't put the shulkers down to see what they contain.
It also helps if you're in a hurry and don't have to search through all of your boxes to find the item you can see it In your inventory.