/usr/share/themes/Piranha/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 7 | full_width_title=true
title_vertical_offset_active=1
title_vertical_offset_inactive=1
button_offset=3
button_spacing=2
active_text_color=#ffffff
inactive_text_color=#c2c2af
|