/etc/xdg/xdg-ubuntustudio/xfce4/ is in ubuntustudio-default-settings 0.54.
This file is owned by root:root, with mode 0o755.
..
/etc/xdg/xdg-ubuntustudio/xfce4/helpers.rc
/etc/xdg/xdg-ubuntustudio/xfce4/panel/
/etc/xdg/xdg-ubuntustudio/xfce4/panel/default.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/thunar-volman.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xfce4-desktop.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xfce4-notifyd.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xfce4-session.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xfprint.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xfwm4.xml
/etc/xdg/xdg-ubuntustudio/xfce4/xfconf/xfce-perchannel-xml/xsettings.xml