gtksourceviewmm  2.10.3
New API in gtksourceviewmm 2.4
Member gtksourceview::SourceView::get_mark_category_background (const Glib::ustring& category, Gdk::Color& dest) const
Member gtksourceview::SourceView::set_mark_category_background (const Glib::ustring& category, const Gdk::Color& color)