Comment 4 for bug 1792934

strace -f debsums module-init-tools:

lstat("/usr/share/doc/module-init-tools", {st_mode=S_IFLNK|0777, st_size=23, ...}) = 0
readlink("/usr/share/doc/module-init-tools", "/usr/share/doc/libkmod2", 4095) = 23
write(2, "debsums: Error: symlink loop det"..., 146debsums: Error: symlink loop detected in path 'usr/share/doc/module-init-tools/changelog.Debian.gz'. Please file a bug against module-init-tools.

So it seems this is a bug in debsums, probably it assumes that there are no symlinked files in the relevant md5sums files.

/var/lib/dpkg/info/module-init-tools.md5sums file is just one line:

c629c0d493d1b6559648de3f63d398d9 usr/share/doc/module-init-tools/changelog.Debian.gz

But /usr/share/doc/module-init-tools is a symlink. And module-init-tools (24-1ubuntu3.2) itself is a pretty empty package, it just has that one file anyhow, and nothing depends on it, it can be removed. (It's only available in bionic anyway.)