BG0 third-party notices

heic-to 1.5.2

BG0 ships a minimally modified heic-to 1.5.2 browser module as a standalone
runtime asset. The modification selects a collection's primary image instead
of relying on libheif's top-level image ordering. It is loaded through its
public ES module interface only when the browser needs the HEIC/HEIF fallback.
The module can be replaced with a compatible modified build without rebuilding
@bg0/browser.

heic-to and its bundled libheif 1.22.2 and libde265 1.0.16 decoder components
are licensed under the GNU Lesser General Public License, version 3 or later.
The LGPL terms are available beside this notice as heic-to-LICENSE.txt,
together with the incorporated GNU GPLv3 terms as GPL-3.0.txt.

Exact corresponding source archives are available under the source/ directory:

- heic-to-1.5.2.tgz (SHA-256 a301b46a2e5a2a050c44d7c1655d63b4c17415312ebcfa82920e950baffc5a7f)
- libheif-1.22.2.tar.gz (SHA-256 af30a8b32dfbc1dc86a7f0f55a53107dad35010a65ebf1feb468082e402b11e0)
- libde265-1.0.16.tar.gz (SHA-256 ed12c931759c1575848832f70db5071a001ac813db4e4f568ee08aef6e234d4e)

The same directory includes heic-to-primary.patch, guarded-transform.ts, and
BUILD.md, which document the source modification and reproduce the exact
production artifact from the pinned upstream distribution file.

## BiRefNet browser models

BG0 downloads one of two MIT-licensed ONNX exports. The weights are not bundled
in this repository or package; their original license applies when downloaded
and cached in the browser.

- Full BiRefNet: `naddy24/birefnet-512-webgpu`, revision
  `ca02a86c094927479e2be583abe87f8ea73fcfda`. This browser-compatible 512px
  Swin-L export derives from `onnx-community/BiRefNet_512x512-ONNX` and
  `ZhengPeng7/BiRefNet_512x512`; empty ScatterND operations were removed.
- Lite fallback: `studioludens/birefnet-lite-512`, revision
  `4a3c40c36c94093cc1e724d9ea428b8fa4b57dc7`, derived from
  `ZhengPeng7/BiRefNet_lite`.

Model cards, licenses, attribution, limitations, and citation:

- https://huggingface.co/naddy24/birefnet-512-webgpu
- https://huggingface.co/onnx-community/BiRefNet_512x512-ONNX
- https://huggingface.co/ZhengPeng7/BiRefNet_512x512
- https://huggingface.co/studioludens/birefnet-lite-512
- https://github.com/ZhengPeng7/BiRefNet