"The Internal Revenue Service issued a final reminder today [June 30] to nearly 1.5 million taxpayers across the country to claim their refunds for tax year 2019 by filing before the July 17, 2023, deadline."
The $900 figure that you saw is a rough average for all the people who might have been eligible for a refund but did not file a 2019 tax return. It does not mean that your particular refund would have been $900.