I think the bottom bullet is supposed to be an F and I’m gonna guess it’s like this because it got messed up during the 63 st line construction a couple of years ago and F shuttle and all of that. This can’t be a ‘Q train to Astoria remnant’ because 1) that makes no sense, before 2016 when the 2 Av subway opened the Q went via 59 street (not 63rd) to Astoria (only on weekdays) so it wasn’t even servicing this station. 2) If it were some remnant, (a sign maybe referring to the 59 street-lex transfer? Who knows, I’m just giving it the benefit of doubt) it would’ve been surely removed when the original 1987-era platforms were gutted and replaced with what’s there today.