All reports of debconf-is-not-a-registry for the archive. The extended description of this tag is:
In the Unix tradition, Debian packages should have human-readable and human-editable configuration files. This package uses debconf commands outside its maintainer scripts, which often indicates that it is taking configuration information directly from the debconf database. Typically, packages should use debconf-supplied information to generate configuration files, and -- to avoid losing configuration information on upgrades -- should parse these configuration files in the config script if it is necessary to ask the user for changes.
Some standalone programs may legitimately use debconf to prompt the user for questions. If you maintain a package containing such a program, please install an override. Other exceptions to this check include configuration scripts called from the package's post-installation script.
Refer to Debian Developer's Reference section 6.5.1 (Do not abuse debconf) and the debconf-devel(7) manual page for details.
This tag has not been emitted in any package tested by Lintian.