Here is a great listing of CA grants and loans and tax treatment:

https://gpwcpas.com/grant-credit-loan-and-other-relief-comparison-chart/

You will be able to use that to be more specific as which grant this is. You asked about:

California Small Business COVID-19 Relief Grant

But I don't see that combination of words. I see:

CA Relief Grant

and

Small Business debt relief

But not in combination. And unfortunately, right now, the Search results function here is not working, as can be read in the Intuit announcement linked at the top of the web pages:

https://proconnect.intuit.com/community/community-basics/discussion/intuit-faqs-we-couldn-t-find-tha...