How Does USCIS calculate 60 days post termination of Employment on H1.?

Does any one know how does USCIS know that 60 days are over after end of H1 employment.?
Does it only check Paystubs.?
Thank you .

They start counting it based on the last day of employment at your employer. It usually is based on Employer sending the withdrawal letter and pay stubs. Also, the employer has I-9 compliance things that they do. In future, USCIS could ask for you to prove status and if they believe you violated status, then you will be in troubleā€¦