<https://github.com/freebsd/freebsd-src/blob/d8e59012e29dee301a7af5c2a70749637319fafc/UPDATING#L2196-L2212> (2020-10-31) directs users to always update the ZFS boot block, and offers example use of gpart(8) that includes an EFI use case. Later <https://www.freebsd.org/releases/13.0R/relnotes/#boot> directs users to _stop_ using gpart to update EFI system partitions.
Please feel free to work with your mentor to update src/UPDATING .
(In reply to Li-Wen Hsu from comment #1) I'm not sure how best to edit content such as this. Advice from people with subject expertise will be appreciated.