Adds "Block Replacer" item. Replaces block it is used on with the block in your offhand.
The main feature of the Block Replacer is that it doesn't modify any other nearby blocks. This lets you for example replace the block underneath redstone dust without breaking it. This is very helpful for changing things in post in projects, for example colored wiring for redstone contraptions previously built out of one block.
The Block Replacer is a creative-mode only item. It works in survival, but is not obtainable.