with kf6 progressing nicely here's a first conflict report of files that appear in both kf6 and kf5 under the same name. this largely affects translations and docs it seems. this list may not be entirely comprehensive, I've only thrown together a script in a couple minutes.
one question is whether ECM should be co-installable, not sure if that has been discussed report for /usr: https://collaborate.kde.org/s/3gz2KfoGLsS4TF5 furthermore the following files outside /usr clash between kf6 and 5: '/etc/xdg/accept-languages.codes' '/etc/xdg/kshorturifilterrc' '/etc/xdg/autostart/baloo_file.desktop' '/lib/udev/rules.d/61-kde-bluetooth-rfkill.rules' HS