The tag is present in Lintian version 2.104.244. That is the most recent version we know about.
Files-Excluded field in
used to exclude files from upstream source packages such as when they
violate the Debian Free Software Guidelines
However, this field will be ignored by uscan(1) if the
file is not declared as following the
Please ensure your
debian/copyright file starts with the
Refer to the uscan(1) manual page for details.