TT does not receive tax refunds or stimulus checks. Which stimulus payment do you mean, #1, #2 or #3?
Banking information is received in a number of ways:
When there is no banking information available, before issuing a U.S Treasury check or EIP Card, Treasury's Bureau of Fiscal Service has provided IRS account information from agencies issuing benefit payments including the Office of Personnel Management, Railroad Retirement Board, Social Security Administration, Thrift Savings Plan, and Department of Veterans Affairs. The banking information can be either where a U.S. Government payment was sent or an account where an individual paid the U.S. Government.
This information is for the 3rd stimulus payment and more information can be found here. Direct deposit information for a tax refund comes from your Form 1040.