[sugar] Posting an activity bundle

[Jonathan Blocksom]

I have a sample activity bundle I'd like to put up on the wiki.  I had
created a .tgz of the bundle and the wiki gave me a warning at the
upload screen about the .tgz extension not being valid for an image
(even when I clicked the "ignore warnings" button).

What's the procedure for uploading an activity bundle?  Is .tgz the
preferred format, or is there another extension?  I couldn't see
anything on the wiki about this.

Thanks,
Jonathan