Probably will come in handy since I'm going to install an expensive sub and amplifier in the trunk.
In all of my trips to tha junk yard, which were many I've never seen this cover.
They must remove it to remove the battery and throw it somewhere...

Most owners remove them for the added height in the cargo compartment. They get left in the corner of the garage when the x5 gets traded in or sold. I've had to buy them separate from the vehicle we've purchased more often than not.