In the world of Windows 8.1 installation, the (Edition Configuration) file is a powerful "cheat code" used to bypass the initial product key prompt or force the installer to display a menu of different Windows editions (like Pro vs. Core). Microsoft Learn What is ei.cfg?
When you download an official Windows 8.1 ISO from Microsoft, that single ISO often contains the installation files for multiple editions, such as: ei.cfg windows 8.1