It's listed as a feature in the collector's version of the expansion on the eq2 site. I think it means you can have an extra boss in your dungeons. I agree that the description isn't very descriptive though.
Ohhhhh, yes. I forget which is which, but I ended up with these 3 bosses, one from the standard, the others from collectors: http://u.eq2wire.com/item/index/551828514 http://u.eq2wire.com/item/index/1210187227 http://u.eq2wire.com/item/index/3906532341 Many more bosses available by spending dungeon marks on the boss packs. EQ2 wire has the best "checklist" ability out there for seeing what you have and don't have.
