This is just a kind of automated 'help' funtion triggered by the 'mouse over' event. This happens not on the original 8ch site.  https://qmap.pub/ also has this feature, see drop 2469 ('CA'). qmap.pub has fixed it for the 2478 because the 'L' and the 'AS' are not abbreviations in that drop. The function uses a list of Q-typical abbreviations or synonyms, like HRC, Hussein etc. These are underlined (dotted). So in my opinion there's no hidden meaning.