/usr/share/doc/gcc-doc/gccint.html is in gcc-doc 4:5.3.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-doc/../gcc-5-base/gccint.html
/usr/share/doc/gcc-doc/../gcc-5-base/gccint.html