Emulation allows your PC to mimic an Xbox 360 console. You then download the Xbox 360 version of the game (which is already smaller than the Xbox One version) and run it through an emulator. Many repackers compress these emulator-ready folders into smaller packages.
Forza Horizon 2 Highly Compressed For PC: Everything You Need to Know Forza Horizon 2 Highly Compressed For Pc
This is the critical fact most searchers miss. Microsoft and Playground Games never released Forza Horizon 2 for Windows PC. The game was exclusive to Xbox 360 and Xbox One. Unlike Forza Horizon 3, Forza Horizon 4, and Forza Horizon 5—which all received stellar PC ports—. Emulation allows your PC to mimic an Xbox 360 console
Before diving into downloads, let's clarify what "highly compressed" means in the gaming world. Forza Horizon 4
To summarize: