The LevelEditor requires:
In addition, the LevelEditor has the Authoring Tools Framework (ATF) tool as a prerequisite; the required ATF code is included with the LevelEditor download package. See the ATF GitHub site for more information about ATF.
To modify the LevelEditor, you also need Microsoft Visual Studio® 2010 (or later), including all current Service Packs. See the LevelEditor Programming Guide for more information about modifying the LevelEditor.