/usr/share/xfce4/terminal/colorschemes/xubuntu-dark.theme is in xubuntu-artwork 18.04.5.
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 10 11 | [Scheme]
Name=Xubuntu Dark
ColorForeground=#b7b7b7
ColorBackground=#131926
ColorPalette=#000000;#aa0000;#44aa44;#aa5500;#0039aa;#aa22aa;#1a92aa;#aaaaaa;#777777;#ff8787;#4ce64c;#ded82c;#295fcc;#cc58cc;#4ccce6;#ffffff
ColorSelection=#163b59
ColorSelectionUseDefault=FALSE
ColorCursor=#0f4999
ColorBold=#ffffff
ColorBoldUseDefault=FALSE
TabActivityColor=#0f4999
|