Absolute joke. Emphasis is mine:

… protected by a TPM and recovered automatically only by early boot software that is authorised to access the data

later on in the article it talks about how the packages are now going to be supplied:

Namely, the bootloader (shim and GRUB) and kernel assets will be delivered as snap packages (via gadget and kernel snaps), as opposed to being delivered as Debian packages. As such, it is the Snapd agent which will be responsible for managing full disk encryption throughout its lifecycle.

Looks like snap will be the future for Ubuntu