>>3946598XHK = Honeycomb (Hanikamu). The numbers before it possibly mean H I D A M A R I S K E T C H and they're mostly the same in every episode. They only became set in stone in Hoshimittsu though, in 365 they seem to be much more random.
The bottom right HK*01 = episode number, 091B refers to the scene/cut number. You can see it increasing during the episodes every time it cuts away to something new. Don't ask what B is here, as earlier seasons had "Season/Episode/A or B part of the episode" there, but it's unlikely B refers to the episode part in this case.
Guess the episode of pic related.
