Orphaned datablocks are those which have either: * 0 users * A "fake" user only In the case of the former, they will be quietly discarded from the file on the next save + reload. Hence, it is helpful to have a view where you can confirm which ones fall into this category and might be worth saving. We also include datablocks with a fake user only so that datablocks given a user above can have that easily turned off again (in case the user makes a mistake). Another benefit of showing these is that it become easier to remove fake users from datablocks you no longer want retained without having to hunt for them.