GRUB 2.0 submenus on Debian Jessie/Sid

I rebooted into a new kernel a few weeks ago and was greeted by a two-level menu that came with GRUB 2.0.

New in 2.00:
* Appearence: [sic]
* Menu is organised with submenus.

There is a bug requesting an option to disable this here:

This change adds another layer to grub-reboot, with menus delimited by > characters. There is an explanation of this in the GRUB manual but the Ubuntu wiki has more complete examples.