All reports of license-problem-gfdl-invariants-empty for the archive. The extended description of this tag is:

The given source file is licensed under GFDL, but without any precision about the presence of invariant sections, front-cover or back-cover text.

GFDL license explicitly requests you to document this non presence. .

Refer to and for details.

Severity: minor, Certainty: possible

Check: cruft, Type: source

This tag has not been emitted in any package tested by Lintian.