Trish's note is a paper note in Fallout 4.
Location
It is carried by Trish during the quest Diamond City Blues. It can be obtained from her corpse.
Notes
The image depicts the front of the Four Leaf fishpacking plant, and its many laser tripwires. They must be triggered in the order shown to reveal the secret entrance to Marowski's chem lab. Companions can interrupt the activation sequence; instructing them to hold position is recommended.