Actually, this would be impractical. Quote from Carthage README.md on Github :
Along the way, Carthage will create some assembly artifacts. The most important of these is the Cartfile.resolved file, which lists the versions that were actually created for each structure. Be sure to commit your Cartfile.resolved file, because anyone using the project will need this file to create the same versions of the framework.
After you have completed the above steps and made your changes, other users of the project only need to get the repository and run boothrap for kathaj to start working with the frames you added.