This is a companion data pack for Mouse Wheelie that allows certain features that would normally require a modded server on Vanilla.
To be exact, this concerns tool picking and auto refilling on Minecraft 1.21.4 and above.
Just chuck it on your server and reconnect with your client.
Mouse Wheelie should then automatically detect that the data pack is present and enable the related features.
You can test it working properly by running /trigger mousewheelie_companion_pick_from_inventory set 5
to swap your main hand item with the fifth inventory slot.
