Right here:

Q. If governments use Fund payments as described in the Fund Guidance to establish a grant program to support businesses, would those funds be considered gross income taxable to a business receiving the grant under the Internal Revenue Code (Code)?

A. Yes. The receipt of a government grant by a business generally is not excluded from the business's gross income under the Code and therefore is taxable. However, a grant made by the government of a federally recognized Indian tribe to a member to expand an Indian-owned business on or near reservations is excluded from the member's gross income under the general welfare exclusion.

https://www.irs.gov/newsroom/cares-act-coronavirus-relief-fund-frequently-asked-questions