The official GEOS code repository is the GIT repository (http://git.osgeo.org/gogs/geos/geos.git). Clone with: `git clone https://git.osgeo.org/gogs/geos/geos.git` Use your [http://www.osgeo.org/osgeo_userid OSGeo Userid] (same as this trac instance) to contribute Nightly snapshot can be found on http://geos.osgeo.org/snapshots/ A number of CodeMirrors do exist for users and contributor's convenience.