This is the 1.16 branch, see the 1.12 version here!
Item magnets are very helpful when mining, however they can disrupt item-based automation, such as the Atomic Reconstructor from Actually Additions. The Demagnetizer is a solution to this, which prevents item magnets from functioning within an area around them.
Demagnetizers can also be filtered or redstone controlled, so that they only activate when necessary. The Advanced Demagnetizer has a larger range and more filter slots.
If your mod has an Item Magnet, do not pick up items if the PreventRemoteMovement NBT tag exists on the EntityItem.
If your mod has a item collector block (e.g. the Ranged Collector or the Vacuum Chest), do not pick up items if the PreventRemoteMovement NBT tag exists on the EntityItem, but if the AllowMachineRemoteMovement NBT tag exists, ignore the previous NBT tag. This is to ensure that Item Magnets do not pick up items on conveyors or demagnetized items, while also ensuring that item collector blocks are not restricted by the Demagnetizer.
For more information, see this github issue.