bug#63937: feature request: add or document ability to write to /etc/default/grub from grub service

[Nathan Dehnel]

I want to implement grub fallback on boot failure for a remote machine
so I need to write this to /etc/default/grub

export GRUB_FALLBACK="1 2...{number of entries}"
GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

Thanks