/usr/share/themes/Elberg/xfwm4/themerc is in xfwm4-themes 4.10.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | full_width_title=false
button_spacing=0
button_offset=1
button_layout=O|HMC
active_text_color=#ffffff
inactive_text_color=#d9d9d9
|