The format used to define the hard disk partitions in computers with UEFI startup firmware. The GUID Partition Table (GPT) replaces the previous master boot record (MBR). GPT partitions can hold ...

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In the resulting Disk Management program, right-click the drive’s gray box on the left. If you see a “Convert to GPT Disk” option—which will probably be grayed out—you’ve got an MBR drive.

I've neve used them personally but I know parted can create them and it looks like the kernel option is CONFIG_EFI_PARTITION which is on by default in Debian, I don't have an Ubuntu machine to ...