/usr/share/gtk-doc/html/webkitgtk is in libwebkitgtk-dev 2.4.0-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/gtk-doc/html/../../doc/libwebkitgtk-dev/html
/usr/share/gtk-doc/html/../../doc/libwebkitgtk-dev/html