Updating from virt-install 1.3.2-3 to 1.3.2-4 didn't work. Several files owned by no package cause a conflict. Since I never build anything virt related myself and Arch always was up-to-date, there must have been an issue with an update, that didn't removed those files.
Who might be the culprit, pacman? Or virt-install from community?
I didn't report a bug, since assumed the culprit is virt-install, than likely an old package version and maybe the culprit is something else.
The issue is solved, but I still don't know the cause for the issue:
$ pacman -Qo /usr/share/virt-manager/virtcli/__init__.pyc error: No package owns /usr/share/virt-manager/virtcli/__init__.pyc
$ ls -l /usr/share/virt-manager/virtcli/__init__.pyc -rw-r--r-- 1 root root 189 Oct 5 16:50 /usr/share/virt-manager/virtcli/__init__.pyc
$ sudo pacman -S virt-install virt-manager [snip] Packages (2) virt-install-1.3.2-4 virt-manager-1.3.2-4 [snip] error: failed to commit transaction (conflicting files) virt-install: /usr/share/virt-manager/virtcli/__init__.pyc exists in filesystem [snip] Errors occurred, no packages were upgraded.
$ sudo pacman -Q virt-install virt-manager virt-install 1.3.2-3 virt-manager 1.3.2-3
$ sudo rm -r /usr/share/virt-manager/
$ sudo pacman -S virt-install virt-manager [snip] warning: could not get file information for usr/share/virt-manager/ [snip]
$ sudo pacman -S virt-install virt-manager warning: virt-install-1.3.2-4 is up to date -- reinstalling warning: virt-manager-1.3.2-4 is up to date -- reinstalling [snip] Packages (2) virt-install-1.3.2-4 virt-manager-1.3.2-4 [snip, no warning, no error]