In general, is there a way to check what version a file from a given UEFI firmware bundle is (e.g. from commandline or similar), other than "just knowing" which .zip file you downloaded?Good question. I do not know...
strings -8 /boot/RPI_EFI.fd Mine is pretty old and shows: Built : 16:56:46, Jan 7 2022 v2.6(release):