Hi there,
Unfortunately, because this is the Developer Preview there isn't
documentation right now about all the properties available. However,
the good news is that you can look in the logs that Google App Engine
generates for your robot in your dashboard (choose Info from the
drop-down menu under your application), and you can manually read the
JSON string and get the "properties" content. I've tried to
programmatically print this collection out to the screen, but I got a
Python error reading something like "too many elements". But, it is
possible.
Jason :)