The tag is present in Lintian version 2.104.232. That is the most recent version we know about.
The version of this package contains
debian, but a misleading upstream version mangling occurs in
debian/watch file. Since the
dfsg string is not
part of the upstream version and its addition is Debian-specific, the
debian/watch file should use the dversionmangle option to
remove, instead of adding in uversionmangle, the
comparing version numbers.
Refer to https://wiki.debian.org/DEHS for details.