package imagemagick-6-common 8%3a6.9.10.23%2bdfsg-2.1ubuntu11 failed to install%2fupgrade%3a be%c3%a1ll%c3%adt%c3%b3f%c3%a7jl-elt%c3%a9r%c3%a9s megjelen%c3%adt%c5%91 subprocess returned exit status 127

I was upgrading from KUbuntu 18.04 to 20.04 because of graphics driver issues (I have no GUI right now :( I'm doing it on tty2) and `do-release-upgrade` gave me this error message at the end. At some point during installation, I was asked to choose between my `policy.xml` and the package maintainers' (I've enabled PDF support). I chose to view the diff, but instead, a "subprocess returned exit code 127" message was issued, and dpkg (seemingly) continued. Then, when all other packages were configured, it asked me to file the bug report. There were other configs I had reviewed before with the "show diff" option, and it worked fine apart from this one.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: imagemagick-6-common 8:6.9.10.23+dfsg-2.1ubuntu11
ProcVersionSignature: Ubuntu 4.15.0-99.100-generic 4.15.18
Uname: Linux 4.15.0-99-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
Date: Thu May 14 01:32:00 2020
Dependencies:

ErrorMessage: beállítófájl-eltérés megjelenítő subprocess returned error exit status 127
InstallationDate: Installed on 2016-08-01 (1381 days ago)
InstallationMedia: Kubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
PackageArchitecture: all
Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18rc1, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2
SourcePackage: imagemagick
Title: package imagemagick-6-common 8:6.9.10.23+dfsg-2.1ubuntu11 failed to install/upgrade: beállítófájl-eltérés megjelenítő subprocess returned error exit status 127
UpgradeStatus: Upgraded to focal on 2020-05-14 (0 days ago)
modified.conffile..etc.ImageMagick-6.type-urw-base35.xml: [deleted]
mtime.conffile..etc.ImageMagick-6.policy.xml: 2019-01-23T16:14:26.063962