Technically, the file is a keygen: a small executable program designed to generate fake product keys and activation codes that mimic genuine Autodesk licenses. When run, it bypasses the software's built-in licensing verification, tricking the program into thinking the user has a legitimate perpetual license.
The "Xf-adsk2015-x64" keygen is a relic of a bygone era—when software was physical, expensive, and difficult to access legally. Today, Autodesk and other CAD providers have adapted. They offer free educational licenses, inexpensive subscriptions, and even free tiers for hobbyists. Xf-adsk2015-x64