Earth Reader is a news reader that runs on various devices and is synchronized without any particular centralized proprietary services.
Earth Reader for Mac is a native Mac app of Earth Reader. It currently is heavily under development. You need Python 3.3 or higher to try it out. You can run it by the following instruction:
$ python3 setup.py py2app -A
$ dist/Earth\ Reader.app/Contents/MacOS/Earth\ ReaderLicensed under GPLv3 or later.