Can't find documenation but:

HOWTO

export PBS_FINGERPRINT=xx
export PBS_PASSWORD=yy
export PBS_REPOSITORY=someuser@pbs@pbs-server.example.com:Mydatastore

Find your snapshots

proxmox-backup-client snapshot list

Seems you need to add .fidx to the snapshot name from the list

vm/105/2024-01-02T20:53:25Z drive-scsi0.img.fidx  /dev/pve/vm-105-disk-0 --verbose