Comment 21 for bug 1916250

I followed the test case on a focal chroot whoose sources.list file I modified to impish and the package install did not fail.

Preparing to unpack .../7-libsignon-glib2_2.1-3ubuntu0.21.10_amd64.deb ...
Unpacking libsignon-glib2:amd64 (2.1-3ubuntu0.21.10) ...
Selecting previously unselected package gir1.2-signon-2.0:amd64.
Preparing to unpack .../8-gir1.2-signon-2.0_2.1-3ubuntu0.21.10_amd64.deb ...
Unpacking gir1.2-signon-2.0:amd64 (2.1-3ubuntu0.21.10) ...
Replacing files in old package gir1.2-signon-1.0 (1.14+17.04.20161117-0ubuntu5) ...
Preparing to unpack .../9-libsignon-glib-dev_2.1-3ubuntu0.21.10_amd64.deb ...
Unpacking libsignon-glib-dev:amd64 (2.1-3ubuntu0.21.10) over (1.14+17.04.20161117-0ubuntu5) ...
Setting up libtirpc-common (1.3.2-2) ...
Setting up libsepol1-dev:amd64 (3.1-1ubuntu2) ...
Setting up libfakeroot:amd64 (1.25.3-1.1ubuntu2) ...
Setting up fakeroot (1.25.3-1.1ubuntu2) ...
Setting up rpcsvc-proto (1.4.2-0ubuntu5) ...
Setting up libffi8:amd64 (3.4.2-1ubuntu5) ...
Setting up libc-dev-bin (2.34-0ubuntu3) ...
Setting up libtirpc3:amd64 (1.3.2-2) ...
Setting up libselinux1-dev:amd64 (3.1-3build2) ...
Setting up libglib2.0-0:amd64 (2.68.4-1ubuntu1) ...
No schema files found: doing nothing.
Setting up libglib2.0-bin (2.68.4-1ubuntu1) ...
Setting up libsignon-glib2:amd64 (2.1-3ubuntu0.21.10) ...
Setting up libtirpc-dev:amd64 (1.3.2-2) ...
Setting up libnsl2:amd64 (1.3.0-2build1) ...
Setting up libgirepository-1.0-1:amd64 (1.68.0-1build2) ...
Setting up libglib2.0-dev-bin (2.68.4-1ubuntu1) ...
Setting up gir1.2-glib-2.0:amd64 (1.68.0-1build2) ...
Setting up libnsl-dev:amd64 (1.3.0-2build1) ...
Setting up gir1.2-signon-2.0:amd64 (2.1-3ubuntu0.21.10) ...
Setting up libc6-dev:amd64 (2.34-0ubuntu3) ...
Setting up libmount-dev:amd64 (2.36.1-8ubuntu2) ...
Setting up libsignon-glib-dev:amd64 (2.1-3ubuntu0.21.10) ...
Setting up libglib2.0-dev:amd64 (2.68.4-1ubuntu1) ...
Processing triggers for libc-bin (2.34-0ubuntu3) ...