Firefox 74 is not open for new sign-offs. It's either too early or too late to do that. There is a current accepted sign-off, which is used for shipping Firefox 74.
|Feb. 25, 2020
|1734 obsolete, (75%)
Pontoon: Update Romansh (rm) localization of Lightning Localization authors: - Martin <firstname.lastname@example.org>
Martin <email@example.com> rev 9d314cd1b15a
Francesco Lodolo accepted sign-off by Francesco Lodolo on Feb. 26, 2020