I often scroll through the newest questions https://photo.stackexchange.com/questions and find that one question has been highlighted in a darker grey panel. At time of writing, the question titled
LR Develop Module showing negative image!, asked a few hours ago, is one such example.
I've wondered this for quite a long time, and I'm still unable to see any correlation with eg user type, number of answers, comments, views or anything? I also can't find anything in meta or help when searching for 'grey' or 'gray'