Yes, it is in Section 4.01(1) of that Rev. Proc.:
(1) Elections to waive carryback under § 172(b)(3) for NOLs arising in taxable years beginning in 2018 or 2019. A taxpayer within the scope of this revenue procedure may elect under § 172(b)(3) to waive the carryback period for an NOL arising in a taxable year beginning in 2018 or 2019. Such an election must be made no later than the due date, including extensions, for filing the taxpayer’s Federal income tax return for the first taxable year ending after March 27, 2020.
