/usr/share/themes/Silverado/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 8 9 | full_width_title=true
button_offset=3
button_spacing=1
button_layout=O|HMC
title_vertical_offset_active=0
title_vertical_offset_inactive=0
title_alignment=left
active_text_color=#000000
inactive_text_color=#8f8f8f
|