$ dnf system-upgrade download --releasever=23 ... Error: Transaction check error: file /usr/share/man/man5/attr.5.gz from install of man-pages-4.00-4.fc23.noarch conflicts with file from package attr-2.4.47-10.fc22.x86_64 man-pages should conflict with version of attr less than the one in which attr.5.gz was removed (Conflicts: attr < 2.4.47-14 is probably fine). This is a problem because the conflict is detected too late, in the transaction check phase. Version-Release number of selected component (if applicable): man-pages-3.81-3.fc22.noarch attr-2.4.47-10.fc22.x86_64
The only way I'm able to reproduce this is when I exclude attr package from being updated in dnf.conf. If I don't do that, both packages are updated, so there is no conflict: attr-2.4.47-10.fc22 -> attr-2.4.47-14.fc23 man-pages-3.81-3.fc22 -> man-pages-4.00-4.fc23 Can you provide more information (dnf logs)?
One way to encounter this is to have a failed upgrade with more than one version of the package installed. Another would be to have both attr.x86_64 and attr.i686 installed and attempt to upgrade just one of them. You are right that this is not something that would be normally encountered, but having proper conflicts helps: instead of having to manually remove packages and resolve the conflict, the system would uninstall the conflicting package and the problem would be resolved automatically.
man-pages-4.00-5.fc23 has been submitted as an update to Fedora 23. https://bodhi.fedoraproject.org/updates/FEDORA-2015-4d56cdd503
OK, conflict added. f23: http://pkgs.fedoraproject.org/cgit/man-pages.git/commit/?h=f23&id=ba49d3769807e7b8d07d15cce6e9347f9b5a107f master: http://pkgs.fedoraproject.org/cgit/man-pages.git/commit/?id=9bf22688d77e9a0c640724c08468276d47ea4845
man-pages-4.00-5.fc23 has been pushed to the Fedora 23 testing repository. If problems still persist, please make note of it in this bug report. If you want to test the update, you can install it with $ su -c 'dnf --enablerepo=updates-testing update man-pages' You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2015-4d56cdd503
man-pages-4.00-5.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.