Comment 9 for bug 1521132

Answer in Debian report:

The package is a Ubuntu version, and does not even exist in Debian.
The -signed package is probably secureboot related, which as far as I
know Debian has no support for at this time.

And of course in BIOS mode secureboot does not apply and non efi grub
is used, so it is very very different.

So the bug report to Ubuntu makes sense, while the one to Debian does
not since there is no such package.

--
Len Sorensen