Most 1620 trainers for Batman: Arkham Knight include a variety of "hotkeys" to trigger the following effects:

"Oracle," Batman strained, fighting the invisible script that forced his hand toward the 'Enter' key. "Find the source code. The string '1620'. Delete it."

: Open the trainer first, then launch the game. Most trainers will give an audio confirmation (like "Trainer Activated") once they hook into the game process. 100% Achievement Guide: Batman - Arkham Knight Part 1