Is it possible you have plugins in your browser that do additional content/headers checks? Because I just successfully downloaded a fatjar and launched it as described in README. But indeed there’s a subtle bug (indicated by ERR_CONTENT_DECODING_FAILED) that asset is served with Content-Encoding gzip, but in fact not gzipped - in both latest Firefox and Chrome it didn’t cause any problems though - that’s why I suspect 3rd-party extensions on your computer.