Look through the disclosures and agreements you signed on account opening and find out which banks PayPal is using for your account. The linked one above is for a deposit account at Synchrony Bank.
Do you have a PayPal account? If so, I assure you that you signed an agreement. The complaint in this class action lawsuit says that the agreement is a 65-page PDF. You would likely have signed it electronically by clicking an “I agree” checkbox.