The tag is present in Lintian version 2.109.24. That is the most recent version we know about.
The debhelper compatibility version used by this package is marked as experimental by the debhelper developer. You should consider using a stable compatibility version instead.
The compatibility version can be set by specifying
debhelper-compat (= 12) in your package's
Build-Depends, by the legacy
debian/compat file or
even by setting and exporting DH_COMPAT in
debian/rules. If it
is not set in either place, debhelper defaults to the deprecated
compatibility version 1.
Please refer to the debhelper(7) manual page for details.