2020-09-15_21:10:32
Development/DevelopmentTool: For any application, but used during development only. Stuff that helps when making the game but isn't needed when the final shipped product is running. Debugging tools or tools used by content creators.
Editor: For use in Unreal Editor only. Editor module may not be included in shipping games and applications, forbidden by the EULA.
Runtime: For any application at any time. A mixed bag. The core functionality that is always needed will be found here.
ThirdParty: Modules containing code that wasn't written by the developer of the plugin/project/engine.
Programs: For standalone programs.