/usr/include/libcroco-0.6/libcroco/ is in libcroco3-dev 0.6.8-3+b1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libcroco-0.6/libcroco/cr-additional-sel.h
/usr/include/libcroco-0.6/libcroco/cr-attr-sel.h
/usr/include/libcroco-0.6/libcroco/cr-cascade.h
/usr/include/libcroco-0.6/libcroco/cr-declaration.h
/usr/include/libcroco-0.6/libcroco/cr-doc-handler.h
/usr/include/libcroco-0.6/libcroco/cr-enc-handler.h
/usr/include/libcroco-0.6/libcroco/cr-fonts.h
/usr/include/libcroco-0.6/libcroco/cr-input.h
/usr/include/libcroco-0.6/libcroco/cr-num.h
/usr/include/libcroco-0.6/libcroco/cr-om-parser.h
/usr/include/libcroco-0.6/libcroco/cr-parser.h
/usr/include/libcroco-0.6/libcroco/cr-parsing-location.h
/usr/include/libcroco-0.6/libcroco/cr-prop-list.h
/usr/include/libcroco-0.6/libcroco/cr-pseudo.h
/usr/include/libcroco-0.6/libcroco/cr-rgb.h
/usr/include/libcroco-0.6/libcroco/cr-sel-eng.h
/usr/include/libcroco-0.6/libcroco/cr-selector.h
/usr/include/libcroco-0.6/libcroco/cr-simple-sel.h
/usr/include/libcroco-0.6/libcroco/cr-statement.h
/usr/include/libcroco-0.6/libcroco/cr-string.h
/usr/include/libcroco-0.6/libcroco/cr-style.h
/usr/include/libcroco-0.6/libcroco/cr-stylesheet.h
/usr/include/libcroco-0.6/libcroco/cr-term.h
/usr/include/libcroco-0.6/libcroco/cr-tknzr.h
/usr/include/libcroco-0.6/libcroco/cr-token.h
/usr/include/libcroco-0.6/libcroco/cr-utils.h
/usr/include/libcroco-0.6/libcroco/libcroco-config.h
/usr/include/libcroco-0.6/libcroco/libcroco.h