Eclipse EMFStore is a model repository (server) for EMF featuring collaborative editing and versioning of models. Existing versioning systems such as SVN or GIT are focused on textual artifacts and do not work well for models. The EMFStore is a repository and version control system for the Eclipse Modeling Framework (EMF) designed specifically for models. Instead of versioning the textual serialization of a model, it allows semantic versioning of the model and as a result, supports merging and conflict detection more effectively. The EMFStore server can be applied for EMF Model instances and can be integrated in any kind of existing tool.
A detailed description is available here.