/usr/share/doc/chromium-codecs-ffmpeg-dbg/changelog.Debian.gz is in chromium-codecs-ffmpeg-dbg 49.0.2623.108-0ubuntu1.1233.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/chromium-codecs-ffmpeg-dbg/../chromium-codecs-ffmpeg/changelog.Debian.gz