Indeed there is no widespread documentation on how to play with rsync itself. A long time ago I played with the idea of replicating rproxy (https://rproxy.samba

Indeed there is no widespread documentation on how to play with rsync itself. A long time ago I played with the idea of replicating rproxy (https://rproxy.samba.org/ https://rproxy.samba.org/), which was just a cool idea. The results are here (https://rproxy.samba.org/ https://rproxy.samba.org/) but are very very basic, it was just a toy. I did have to invent my own protocol, but I did it over HTTP.