man xpra says
--max-bandwidth=BW Specify the link's maximal receive bandwidth. Xpra will adjust the JPEG quality to match this bandwidth. Specify 0.0 (default) to disable. (requires jpeg encoding)
but this does not tell the user what units are expected. Bytes per second? Bits per second?
This switch is gone from 0.10, and no one should be using jpeg at this point because it is just worse than pretty much every other encoding we support in every aspect!
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/361