FFmpeg source availability for Karuiya 0.9.1

The source companion for this binary release is:

    Karuiya-0.9.1-open-source-sources.zip

It is made available at no charge on the same official HTTPS release page as the matching Karuiya 0.9.1 binary archive. The release page publishes SHA-256 values for both archives. Do not redistribute the binary archive without also preserving access to the matching source companion and these notices.

The companion contains, at minimum:

- FFmpeg commit 1fdbca85aaea513c9cc6c14d347f76543346d3da source;
- BtbN/FFmpeg-Builds commit a99e8230eae00d1cee38f23076a7a1f55cd984e2 scripts and patch set;
- Qt/PySide/Python/PyInstaller and Qt-preview-FFmpeg source archives listed in licenses/SOURCE_ARCHIVE_CHECKSUMS.txt, including Qt Image Formats for the shipped WebP plugin;
- exact filenames, SHA-256 values and official acquisition references for the pinned build-input wheels used to create the public onedir; the complete optional-module wheel archives are not redistributed by Karuiya;
- this exact configure output, binary version output and component evidence.

The two FFmpeg/BtbN archives are also included directly in `licenses/FFmpeg-LGPL/corresponding-source` in the binary package. `ENABLED_DEPENDENCY_SOURCE_REQUIREMENTS.md` records that the BtbN scripts select additional third-party libraries. The release custodian must retain a Karuiya-controlled mirror of all license-required source for those enabled libraries; the archived scripts and upstream repositories are reproducibility evidence but are not treated as a substitute for long-term source retention.

Source and release archives for this version are retained for at least three years after the last distribution of the corresponding binary, subject to confirmation by qualified legal counsel. The official Karuiya release page provides the current source-request contact and process.

This engineering record is not legal advice and does not replace review of the LGPL, each enabled dependency license, codec patent considerations or applicable local law.
