All reports of package-uses-experimental-debhelper-compat-version for the archive. The extended description of this tag is:
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.
Refer to the debhelper(7) manual page for details.
This tag has not been emitted in any package tested by Lintian.