the Xpra log is hardcoded to go in ~/.xpra/xpra-$DISPLAY.log.
It may be useful to be able to tell the server, on the commandline, where to store the log:
xpra start --log-file /path/to/log.log
would be great.
dupe of #213
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/247