/usr/include/kadm5/kadm5-private.h is in heimdal-dev 1.6~rc2+dfsg-9+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/include/kadm5/../heimdal/kadm5/kadm5-private.h
/usr/include/kadm5/../heimdal/kadm5/kadm5-private.h