http://lainyubrp2aabmxhepbttfdbl53dct2inqifs42buvpf6w44uiitbeqd.onion/blog/matrix.html
And yes, of course there are server implementations and clients from individuals here. ...But they are fully imbued with the very spirit of open-source. They are made free of charge, so you can't count on the absence of bugs. They often lack the latest specifications, and many clients are in deep-deep beta.