Is there some reasoning (except "legacy") that screens cannot be called by number only?
Could, for example
$ xpra info 7 xpra initialization error: unknown format for display name: 7
work, instead of fail? (assume active ':7' display)
Try r20967 or later.
I'm really not keen on this sort of fuzzy matching which can lead to unexpected results and subtle regressions. If this causes any problems, I'll remove it.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/2031