grub-mount --version (return code: 0)
grub-mount (GRUB) 2.02~beta2-36ubuntu3.7
grub-mount --help (return code: 0)
Usage: grub-mount [OPTION...] IMAGE1 [IMAGE2 ...] MOUNTPOINT
Debug tool for filesystem driver.
-C, --crypto Mount crypto devices.
-d, --debug=STRING Set debug environment variable.
-K, --zfs-key=FILE|prompt Load zfs crypto key.
-r, --root=DEVICE_NAME Set root device.
-v, --verbose print verbose messages.
-?, --help give this help list
--usage give a short usage message
-V, --version print program version
Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.