# third_party Licensing and Provenance Policy

This file sets the policy for externally-derived material before any of it is
vendored into the `retroDE_ps2` repository. It is deliberately written early
so that provenance discipline is in place from the start rather than
retrofitted.

## Principles

1. No material is vendored into this repository without a recorded source,
   license, and adaptation note.
2. Sony confidential documentation (see "Sensitive sources" below) is
   referenced and studied but is **not distributed** from this repository.
3. Open-source material brought in must carry its original license and
   attribution, and that license must be compatible with the eventual
   retroDE_ps2 distribution terms.
4. BIOS ROM images are **never** committed. Users supply their own dumps.

## Sensitive sources (reference-only, not to be vendored)

The following documents are useful technical references but are Sony
confidential-origin leaks. They inform our contracts but must not be copied
into this repository:

- GS User's Manual v6.0 (Sony Computer Entertainment Inc.)
- VU User's Manual / Emotion Engine Vector Operation Unit Guide (Sony)

Treat these as reference-only. Cite them in contract docs when appropriate,
but do not include excerpts beyond what is defensible under normal
engineering-analysis fair-use practice.

## BIOS and firmware

- Real PS2 BIOS images are copyrighted by Sony and are not distributed here.
- The repository may include checksums, region-identifying metadata, loading
  scaffolding, and test harnesses that expect a user-supplied dump to be
  placed in a known local location.
- If an HLE BIOS stub strategy is adopted in any phase (see BIOS policy
  decision), the HLE code is original to this project and must be written
  from clean-room hardware references, not derived from commercial firmware.

## Imported open-source material

If code from `PCSX2`, `Play!`, `DobieStation`, `ps2dev/ps2sdk`, `gsKit`,
`PSX_MiSTer`, or other open-source projects is ever adapted into this
repository, it must be placed under `third_party/<project>/` with:

- the original upstream URL,
- the original license file,
- the upstream commit or version identifier captured at import time,
- a `NOTES.md` describing local modifications.

License compatibility must be confirmed before the import lands on `main`.

## Status

No external material has been vendored as of 2026-04-16. This file defines
the policy that applies when that changes.
