update-tpn

name	update-tpn
description	Audit and update the THIRD-PARTY-NOTICES.TXT file. Use when the user asks to "update TPNs", "audit third-party notices", "check third-party licenses", or after adding/removing a dependency. Scans submodules, vendored code, NuGet packages, and native libraries to ensure the TPN file is complete and accurate.

Update Third-Party Notices

Audit and regenerate the THIRD-PARTY-NOTICES.TXT file at the repo root.

This file is checked in and shipped as-is in the product NuGet packages. There is no code generation step — this skill replaces the old xaprepare TPN infrastructure.

File Format

The file uses the MicrosoftOSS header format:

xamarin-android

THIRD - PARTY SOFTWARE NOTICES AND INFORMATION
Do Not Translate or Localize

This project incorporates components from the projects listed below.
The original copyright notices and the licenses under which Microsoft
received such components are set forth below.
Microsoft reserves all rights not expressly granted herein, whether by
implication, estoppel or otherwise.

1.  name (url)
2.  name (url)
...

%% name NOTICES AND INFORMATION BEGIN HERE
==========================================
<license text>

==========================================
END OF name NOTICES AND INFORMATION

Entries are sorted case-insensitively by name. Each entry has a numbered TOC line and a license section.

Audit Workflow

Step 1 — Inventory all dependencies

Scan these sources to build a complete list of third-party dependencies:

Git Submodules

Read .gitmodules for all submodules. Current submodules and their license files:

Submodule	URL	License File
Java.Interop	https://github.com/dotnet/java-interop	external/Java.Interop/LICENSE
lz4	https://github.com/dotnet/lz4 (fork of https://github.com/lz4/lz4)	external/lz4/lib/LICENSE
xxHash	https://github.com/Cyan4973/xxHash	external/xxHash/LICENSE
constexpr-xxh3	https://github.com/chys87/constexpr-xxh3	external/constexpr-xxh3/LICENSE
robin-map	https://github.com/xamarin/robin-map (fork of https://github.com/Tessil/robin-map)	external/robin-map/LICENSE
libunwind	https://github.com/libunwind/libunwind	external/libunwind/LICENSE
android-api-docs	https://github.com/dotnet/android-api-docs	(not a third-party dep)

Vendored Source (src-ThirdParty/)

List contents of src-ThirdParty/ directory. Current vendored code and license sources:

Directory	Name	License Source
android-platform-tools-base/	android/platform/tools/base	https://android.googlesource.com/platform/tools/base/+/refs/heads/main/sdk-common/NOTICE (Apache 2.0)
bionic/	google/bionic	https://android.googlesource.com/platform/bionic/ (Apache 2.0)
crc32.net/	force-net/crc32.net	https://github.com/force-net/Crc32.NET (MIT)
StrongNameSigner/	brutaldev/StrongNameSigner	https://github.com/brutaldev/StrongNameSigner/ (Apache 2.0)

Note: Mono.Security.Cryptography/, System.Diagnostics.CodeAnalysis/, System.Runtime.CompilerServices/, and dotnet/ are Microsoft-owned and do not need TPN entries.

NuGet Packages

Search .csproj files for <PackageReference> elements. Current third-party NuGet packages needing TPNs:

Package	Name in TPN	License URL
ELFSharp	KonradKuczynski/ELFSharp	https://elfsharp.it/ (MIT + LLVM)
K4os.Compression.LZ4	MiloszKrajewski/K4os.Compression.LZ4	https://github.com/MiloszKrajewski/K4os.Compression.LZ4/ (MIT)
Xamarin.LibZipSharp	xamarin/LibZipSharp	https://github.com/xamarin/LibZipSharp/ (MIT)
Irony	IronyProject/Irony	https://github.com/IronyProject/Irony (MIT)
Newtonsoft.Json	JamesNK/Newtonsoft.Json	https://github.com/JamesNK/Newtonsoft.Json (MIT)
NuGet.ProjectModel	NuGet/NuGet.Client	https://github.com/NuGet/NuGet.Client (Apache 2.0)
Mono.Cecil	mono/cecil	https://github.com/mono/cecil/ (MIT)
Microsoft.Xml.SgmlReader	lovettchris/SgmlReader	https://github.com/lovettchris/SgmlReader/ (Apache 2.0)

Note: Microsoft-owned NuGet packages (Microsoft., System.) do not need TPN entries.

Vendored Linker Code

The src/Xamarin.Android.Build.Tasks/Linker/External/ directory contains vendored code from the Mono linker:

Source	Name in TPN	License URL
Linker/External/	mono/linker	https://github.com/mono/linker/ (MIT)

Native Libraries (from CMakeLists.txt)

Check src/native/ CMakeLists.txt files for references to external native code. The submodules above (lz4, xxHash, libunwind, robin-map) are compiled into native libraries.

Android SDK Tools

These are downloaded and shipped with the SDK:

Tool	Name in TPN	License URL
aapt2	google/aapt2	https://mvnrepository.com/artifact/com.android.tools.build/aapt2 (Apache 2.0)
bundletool	google/bundletool	https://github.com/google/bundletool (Apache 2.0)
r8	google/r8	https://r8.googlesource.com/r8/ (BSD-3-Clause)
binutils	gnu/binutils	https://sourceware.org/git/?p=binutils-gdb.git;a=tree;hb=HEAD (GPLv3)

libzip (via LibZipSharp NuGet)

LibZipSharp bundles libzip internally:

Source	Name in TPN	License Location
libzip (in LibZipSharp NuGet)	nih-at/libzip	LibZipSharp NuGet Licences/libzip/LICENSE or https://github.com/nih-at/libzip/ (BSD-3-Clause)

Step 2 — Cross-reference

Compare the inventory against the current entries in THIRD-PARTY-NOTICES.TXT:

• Missing entries: Dependencies found in Step 1 but not in the TPN file
• Stale entries: TPN entries for dependencies no longer used
• Incorrect info: Wrong URLs, outdated license text

Step 3 — Update the file

For each change:

1. Add/remove the TOC line (maintain sorted order and renumber)
2. Add/remove the license section (maintain sorted order)
3. For new entries, fetch the license text from the source URL or LICENSE file

Step 4 — Verify

Run grep -cP "^\d+\." THIRD-PARTY-NOTICES.TXT (or Select-String "^\d+\." THIRD-PARTY-NOTICES.TXT on Windows) to confirm the entry count and ordering.