It's a bit hard to see here but I found this unexplored water world a couple weeks ago that appeared to have city-lights on it. It's PRAEA EUQ MY-F B15-0 B3. What're people's thoughts? Bug? Uncontacted industrialized civilization? Breakaway human society? Huge bioluminescent ecosystem? Islands that just look like lights because of contrast?
It's hard to tell here, and it's been a while, but I'm pretty sure they were only visible on the night side, even though they look well lit here, and definitely seemed emissive, not lit.