/dev/null/fr

The /dev/null is a tool from the mod. This tool is used to discard all of a single item type when they are picked up. It has a single inventory slot, which can be accessed through sneak-using it with it pointed at air; it cannot be in reach of another block. The item that is put in there is the "filter" item. Once the stack in that slot is full, all exact items will be immediately discarded on pick-up.

With a block in its slot, the tool can be used to place the block.