The partition is listed under "used devices" because there isn't anything you can do with it. It has to exist though because otherwise grub wont fit -- if you select the partition and then try to "edit" it, there is a blurb about what's going on.
** Changed in: subiquity (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1926600 Title: Ubuntu server 20.04.2 installer hidden partition problem To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/subiquity/+bug/1926600/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs