GitHub has been enhancing its GitHub for Mac application by implementing the Mantle framework, which simplifies creating a flexible model layer in Cocoa or Cocoa Touch. This framework addresses common issues with traditional Objective-C model objects, such as boilerplate code and difficulties with JSON integration, by providing features like reversible transformers and an extensible method for merging new data. Unlike Core Data, which can be complex and cumbersome for simple JSON operations, Mantle streamlines the process, offering higher-order functions and better handling of version migrations. Mantle, which is already utilized in GitHub for Mac's production code, is open for contributions, although it is subject to changes as it continues to evolve, with robust unit test coverage ensuring reliability.