I haven't investigated how they work at all...it's a bit like the icons that appear from other folks who have taken screenshots, I just filter them out to stop the map being so cluttered.I think I have seen some map markers from player generated missions but wasn’t sure what it was at the time! I presume players can edit them and then publish somehow? How do we get them in our maps? I presume there must be lots of them so there must be a filter somewhere selecting only a few?