Neuromod Favor is a note in Prey: Mooncrash.
Transcript[]
Here's those neuromods you asked for. I don't care what you want them for, but you didn't get them from me. Just remember when the time comes: you owe me.
- D
Location[]
The note can be found behind a box under a desk in Ken Mizuki's office (Crew Annex, Administration Level) as part of Joan Winslow's story objective A Little Bird Told Me. It cannot be found at any other point in the game.