Marmalade EDK is Extension Development Kit of the Marmalade SDK, a cross platform development environment.
Marmalade EDK is Extension Development Kit of Marmalade SDK, which is a set of tool to bring native functionality of the platform, on which the application is deployed.
The code is written in native supported language, for example for Android it's Java and for iOS it's Objective C.
EDK is currently supported for Android, iOS, Windows and OSX only. There's no support for Windows phone 8 and BB10 yet.