I have no idea if it is currently supported, planned for continuing support etc.
However, a quick google search yielded plenty of information about what it
does. See for instance, the first hit I got:
http://beeznest.wordpress.com/2005/02/03/rsyncable-gzip/
Suppose you have a file that you wish
I can't find documentation on the --rsyncable option. I've looked at
http://www.gnu.org/software/gzip/
Yet it seems to be in the code.
It would really be nice to have an idea from the documentation what this does,
and how useful it is, and if it's currently supported, planed for continuing
su