/usr/include/ccss-1/ccss/ is in libccss-dev 0.5.0-4.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ccss-1/ccss-cairo/ccss-cairo-grammar.h
/usr/include/ccss-1/ccss-cairo/ccss-cairo-style.h
/usr/include/ccss-1/ccss-cairo/ccss-cairo.h
/usr/include/ccss-1/ccss-gtk/ccss-gtk-grammar.h
/usr/include/ccss-1/ccss-gtk/ccss-gtk-stylesheet.h
/usr/include/ccss-1/ccss-gtk/ccss-gtk.h
/usr/include/ccss-1/ccss/ccss-background.h
/usr/include/ccss-1/ccss/ccss-block.h
/usr/include/ccss-1/ccss/ccss-border-image.h
/usr/include/ccss-1/ccss/ccss-border.h
/usr/include/ccss-1/ccss/ccss-color-parser.h
/usr/include/ccss-1/ccss/ccss-color.h
/usr/include/ccss-1/ccss/ccss-function.h
/usr/include/ccss-1/ccss/ccss-grammar.h
/usr/include/ccss-1/ccss/ccss-macros.h
/usr/include/ccss-1/ccss/ccss-node.h
/usr/include/ccss-1/ccss/ccss-padding.h
/usr/include/ccss-1/ccss/ccss-position.h
/usr/include/ccss-1/ccss/ccss-property.h
/usr/include/ccss-1/ccss/ccss-style.h
/usr/include/ccss-1/ccss/ccss-stylesheet.h
/usr/include/ccss-1/ccss/ccss.h