Incomplete license header for `src/libImaging/Arrow.h`

What did you do?

Reviewed distributed/bundled files.

What did you expect to happen?

License headers of third-party code are applied correctly. Source most likely is https://github.com/apache/arrow/blob/main/cpp/src/arrow/c/abi.h

What actually happened?

Only a minimal header is included, as well as omitting the corresponding copyright data from the third-party licenses: https://github.com/python-pillow/Pillow/blob/9c1097c861420c77af53c7c9af2a1382e2bfaa8b/src/libImaging/Arrow.h#L4-L6 As the arrow project has a NOTICE.txt file, this further violates the terms of the Apache-2.0 license: https://github.com/apache/arrow/blob/main/NOTICE.txt

Additionally, executed changes have to be specified explicitly - doing a short diff of the file I found versus the file shipped by Pillow clearly show omissions and formatting changes.

Relevant sections from the license text: https://github.com/apache/arrow/blob/cb7383c71b7c87d45946eec1ba967472592e036b/LICENSE.txt#L98-L122

What are your OS, Python and Pillow versions?

• OS: irrelevant
• Python: irrelevant
• Pillow: main

Start with src/libImaging/Arrow.h and compare it with the referenced Apache Arrow cpp/src/arrow/c/abi.h and NOTICE.txt. Review the diff for omitted copyright, license, and modification details. Done means the bundled header and related attribution accurately reflect the third-party source and required Apache-2.0 notices.