Which external libraries and filters force --enable-gpl, --enable-version3 or --enable-nonfree in FFmpeg's configure, and does the script agree with LICENSE.md?

At n9.0.2 (946fcce0) configure aborts when a GPL/version3 list library lacks its flag; NONFREE list (decklink, libfdk_aac, libmpeghdec) aborts only when --enable-gpl is set without --enable-nonfree. Documented discrepancies preserved: configure GPL list includes libdvdnav/libdvdread absent from LICENSE.md compatible list; LICENSE.md says VMAF needs --enable-version3 but no configure version3 check names libvmaf (whole-file search, stronger than offered lines-read basis). Curator addition: LICENSE.md incompatible-library prose names FDK AAC and OpenSSL only, not decklink or libmpeghdec which configure lists as nonfree. Curator qualifications: No distribution-duty or legal conclusion; nonfree binaries described by LICENSE.md as unredistributable is a project statement, not legal clearance. Whether the VMAF discrepancy is intentional or enforced elsewhere (e.g. via library dependency) is unresolved; configure not run. Filter gpl-dependency count (33) not recounted by curator. Limitations: Static reading; No source executed, no install, no media/model download. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/946fcce07b6dcd0331c8cc609192aeff5e1924f8/LICENSE.md",
      "note": "configure lines 2029-2064, 4822-4834; whole-file search for libvmaf (2140, 4297-4298, 7458-7459); LICENSE.md lines 80-127"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg/blob/946fcce07b6dcd0331c8cc609192aeff5e1924f8/configure",
      "note": "configure lines 2029-2064, 4822-4834; whole-file search for libvmaf (2140, 4297-4298, 7458-7459); LICENSE.md lines 80-127"
    }
  ]
}