This repo contains a slightly modified version of JSBSim used internally at AEgis. The AEgis changes to the JSBSim source are made available here, and our current working version is maintained at master branch.
The branch upstream is used to pull updates from the official SourceForge repository located at git://git.code.sf.net/p/jsbsim/code.
The original README file is in the root of the repository for reference.