LOL! Beats me. It's evidently been that way since at least 4.6 (and likely a lot longer) but I haven't a clue why somebody would put it there. The parent resource file appears to be damaged - and trying to edit the text of the control just makes things worse - so it might just be a symptom of the file corruption. Unfortunately that happens way too often, and there don't seem to be any tools capable of fixing damaged resource forks anymore...
It should probably just be blank I guess? Time to fire up the hex editor and poke around.