Operates by using a public nightly dump - available here . Faves are public, so they are present in the dump. No other personal interactions with images (expect comments and galleries) available to analyze.
Keep in mind rules #0/6/8. Intentional massive bothering people because of matching faves (especially if they told you that they don’t wish to talk with a strangers) may result in banning.
@LightningBolt
Sorry for that. There are only 1800 users with 20000+ faves. They make a triple load to the server during calculations. Soon i will publish source code and you will able to remove this limit if you able to run the Python server locally