/usr/share/gtk-doc/html/ORBit2 is in liborbit2-dev 1:2.14.19-0.3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/gtk-doc/html/../../doc/liborbit2-dev/ORBit2
/usr/share/gtk-doc/html/../../doc/liborbit2-dev/ORBit2