Comment 11 for bug 1427182

usr/lib/ubuntu-mate/ubuntu-mate-settings-overlay:
* Not a very big fan of this script, especially as you are using a fixed filename. Please rather user mktemp to randomize the name and use a pattern.
* chown -R ${USER}: "${USER_DIR}" -> why do you need to chown as the user, I hope this script isn't used at root? (when is it executed exactly?)

Just a note (not a blocker), we tend to use with rm_conffiles and such <new_version_without_conffiles>~. That enables if you backported to ppa previous version or if there is a SRU (not applicable in this case) to ensure that even if new packages on older series were releases, those would get their conffiles cleaned up as well.