Forza 2012 Webserver Tool
Included in the files of Forza Horizon 2 and Forza Motorsport 5 is this HTML Xbox Live debug tool. It was probably used to test the online functionalities of both games.
The two games have a "Webserver" folder, each with the same content. The only difference is that FH2 has a file named psapi.dll, while FM5 has a file named prebakedIR.dat. Both are on this website.
The code is untouched, asides from the Forza logo (which was originally just a link to the official Forza website) and some http links that were replaced with https. The logo isn't online anymore, so I downloaded it from the Wayback Machine and put it there directly.
There are two HTML pages, Session Calls and Test Page.