/usr/share/doc/libboost-test1.48-dev/changelog.Debian.gz is in libboost-test1.48-dev 1.48.0-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libboost-test1.48-dev/../libboost1.48-dev/changelog.Debian.gz