Dropped Off Bets at Your Place is a written note found in Death of the Outsider.
Transcript[]
I dropped off the betting coin in the safe, and hid your apartment key in the bucket by the door, like you said. You're all set. You owe me TWO bottled rats for helping you this time!
-Ilyra
P.S If you forget the combination again, tally the books over your desk. Maybe they'll uncover your memory.
Location[]
This note can be pick-pocketed off Robbie, the bookmaker for the Eyeless, in the Albarca Baths during the mission One Last Fight.