This Editor is provided by Eclipse in EMF.

Since Kermeta metamodel is an extension of EMOF, it is possible to use this editor to edit Kermeta programs.

This based on the Ecore2Kermeta and Kermeta2Ecore transformations.

With the Ecore representation of your program, you can use the Ecore Model editor (from Eclipse\EMF) or any other Ecore tool (for example Omondo.graphic editor)

This is described with more details in the EMF tutorial: http://www.kermeta.org/docs/html.single/KermetaEMFTutorial/