Quake II engine: copyright (C) 1997-2001 id Software, Inc.
GNU GPL version 2 or (at your option) any later version. See COPYING.txt.

Original upstream source:
https://github.com/id-Software/Quake-2/tree/372afde46e7defc9dd2d719a1732b8ace1fa096e

All 371 original source files are unchanged. External build files
quake2-original.vcxproj and icon.rc target Visual Studio 2026 v145 / Win32.
Exact source and build files are in the companion archive
QuakeII-original-engine-source.zip. Publish that archive alongside the portable
binary download; it need not be inside the launcher ZIP.

To rebuild, extract that archive and run in a VS developer shell:
msbuild quake2-original.vcxproj /p:Configuration=Release /p:Platform=Win32 /m
Output: bin/quake2.exe
