After creating an lxd container in the ZFS storage I deleted the based image by mistake.
Now the ZFS structure looks like:
# zfs list -t all -o name,clones
...
main/containers/mail
...
main/deleted/images/d0...a6e7
main/deleted/images/d0...a6e7@readonly main/containers/mail
...
How can I restore the deleted based image?