What is that? It look perhaps similar to lavender or flax or borage?
Yes. They hope to elicit some kind of reaction from anons and distract from things we're focused on with today's news & happenings.
There's a field in the Options menu (upper right corner) to enable drag + drop. Take a look at that and see if it's checked Yes.
I like it a lot! flashback
Yes.
That's the registration (tail #). This aircraft isn't transmitting a callsign. Exclam probably means the format of the number doesn't make sense to the web server - you'd have to check ADSB FAQ or something. I've never seen exclam before. Question mark yes, when the signal is weak and the decode is uncertain.