helloSystem uses the OpenZFS for the boot disk.
Additionally, the following filesystems are supported in helloSystem, but it cannot be started from those:
exFAT (Windows) once available in quarterly packages
NTFS (Windows; read-write support)
EXT4 (Linux) once available in quarterly packages
Supported filesystems are automatically mounted by automount.
To see how they are mounted, open the Logs utility and attach a disk.