Talk:Tutorial: FAQ/@comment-31356857-20170221010304/@comment-26705246-20170221014558

Those are map lock tags, currently an event exclusive feature. They basically mark a ship as being locked to a specific map (sometimes more than one depending on the event) and that ship can only be sortied to that event map (or any other map that shares the same tag). If you are doing an event map on easy, the tag will still be applied, but the locking mechanic is ignored (so ships aren't map restricted)

More info here - Ship Locking