Removes the cooldown after breaking a block (in survival). Thus allowing you to break slightly faster.
Minecraft has a slight delay of five tick after you break a block. And While this delay is active you cannot break blocks. This is handy in creative so you don't accedentally break too many blocks. But in survival it is annoying and slow.
This makes it so almost instant--breaking feels as fast as it should do. This is because instant-break doesn't have a cooldown.
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