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.
This item cannot be removed from your inventory even if you have completed Diamond City Blues. If the player wishes to remove this note from their inventory, enter the console command player.removeitem 0004427a.