4n1m4L's test logs is a holotape in Fallout 4.
Location
Found in the Institute's Public Works maintenance area during the quest The Nuclear Option (Minutemen).
Transcript
Prototype?
We found this robot locked in one of the secure labs. Looks military, and the limb servos are waaaay beyond what I've been working with. Definitely not RobCo. I wonder what kind of mechanical output these things can do. I'm going to set it up on the treadmill and start it off at 30% output, then ramp it to 75% and collect the data.
I'm so screwed
I tried to stop the simulation after the servo output reached 50% and the first chain snapped but I didn't reach it in time and that thing ran straight through the wall! Oh god I am going to be in so much trouble. Okay, don't panic. Just put it back in the cart and bring it back to the lab and oh crap someone is coming.