Comment 12 for bug 1792497

With the correct sources.list settings, I see:

$ sudo apt install shim-signed
Reading package lists... Done
Building dependency tree... Done
The following extra packages will be installed:
  dmsetup dpkg efibootmgr grub-common grub-efi-amd64-bin grub2-common
  libdevmapper1.02.1 libefivar0 libfreetype6 libfuse2 libpci3 mokutil shim
Suggested packages:
  multiboot-doc grub-emu xorriso desktop-base console-setup fuse
Recommended packages:
  os-prober secureboot-db
The following NEW packages will be installed:
  dmsetup efibootmgr grub-common grub-efi-amd64-bin grub2-common
  libdevmapper1.02.1 libefivar0 libfreetype6 libfuse2 libpci3 mokutil shim
  shim-signed
The following packages will be upgraded:
  dpkg
1 upgraded, 13 newly installed, 0 to remove and 87 not upgraded.
Need to get 6183 kB of archives.
After this operation, 21.6 MB of additional disk space will be used.
Do you want to continue? [Y/n]

And all packages are correctly installed in the right order.