I don't know which version of OzRunways you use, but when I go to select a different map on OzRunways, above the list of selectable maps (VFR, ERC, TAC etc) there is the option to select "Legend".
Despite what many may believe, this is not in fact a compliment regarding the user's piloting skills, but brings up an image of a legend that explains the symbols present on the map...scroll down a bit and theres a U and Biggles's angular birdy symbol with the explanation that it refers to locations where ultralights are present.
I don't believe this is a deliberate removal of information at all, it's been there for ages - that symbol has had that meaning for at least 15-20 years that I know of.