Are these files still needed after upgrade?

[NASbox]

I was cleaning up my main pool I noticed this dataset called jails that appears to be no longer in use. (I upgraded to TrueNAS Core 12.0-U6 directly from FreeNAS v11.3 several months ago.) IIUC iocage has replaced warden, and the iocage dataset appears to have taken over all the jails and plugins.

Code:

NAME                                              USED  AVAIL     REFER  MOUNTPOINT
TANK/jails                                        684M  6.07T      205K  /mnt/TANK/jails
TANK/jails/.warden-template-pluginjail-11.0-x64   684M  6.07T      684M  /mnt/TANK/jails/.warden-template-pluginjail-11.0-x64

Can someone please confirm that "jails" just a leftover from FreeNAS v11.3, that can safely be deleted, and that doing so won't mess up TrueNAS?

Thanks in advance for any guidance you can provide.