several xfce4 components install programs directly in /usr/libexec: /usr/libexec/exo-compose-mail-0.3 /usr/libexec/exo-helper-0.3 /usr/libexec/exo-mount-notify-0.3 /usr/libexec/balou-export-theme /usr/libexec/balou-install-theme /usr/libexec/xfsm-shutdown-helper thunar stuff ... Terminal ... xfconfd.... This is not allowed per FHS, and these libexec scripts should be moved to a subfolder. I suggest putting all the xfce libexec executables under /usr/libexec/xfce4/ several libexec programs already live there.q
Xfconf still installs the migration script to /usr/libexec. Some panel plugins are also installed there it seems (mixer and brightness plugin on my machine). The other ones were fixed by Nick recently. Nick, any idea about the panel plugins?
There is a migration path for plugins. They need to convert the plugin to a library (and install it under $libdir) and use the new macros. This also allows to run the plugin in the wrapper application and switch between in- and exterminal. So ignore the panel plugins, they will start to migrate after 4.8 is released. Everything else should move to $libdir.
No idea why this was reported again garcon, but it also seems to be fixed for core. Not that every dual arch distro agreed; but that's life ;-).