[Mobhack]

Those are units that have been pulled for some reason most probably.

The advantage to doing that is that you still have a template unit existing in any scenario using them so you then don't have to search through looking for orphans with a bad graphic.

So these are deleted units - but not yet fully gone.

Also - some formations may be nation 0, but used as subordinates to larger lumps, those are "part" formations for some complex items, not made available for human purchase.

Andy