/usr/share/doc/libmono-system-web-services4.0-cil/changelog.Debian.gz is in libmono-system-web-services4.0-cil 4.6.2.7+dfsg-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libmono-system-web-services4.0-cil/../libmono-corlib4.5-cil/changelog.Debian.gz