I can not find any usage of the plugin org.eclipse.modisco.omg.gastm. Doesn't modisco use it to create a GAST of a Java AST to build language independent tools on it? Or does it just represent the unused default implementation of the OMG standard currently?
Are there any plans to build tools on it in the future?
The MoDisco project provides the implementation in Ecore of the GASTM metamodel as specified by the OMG ADM Task Force.
Right now there are no specific components in MoDisco directly relying on this metamodel, but this may change in the future and the project is open to all interesting and relevant contributions on that topic.
Anyway, all the generic components from the MoDisco "Infrastructure" layer can already work on GASTM models (as on any models in general).
The GASTM metamodel can also be taken and reused as part of any model driven reverse engineering process or tool.