Well, although image keypoints are detected between image borders and matched in stitched panoramas, this data is not saved in the output cube map.
Rather, as panoramas go here on Photosynth.net, ever since their mobile panorama apps launched in 2011 we've had users asking here on the forum for a way to save a local copy of their panos that they'd uploaded to their Photosynth.net account.
This applied for folks who had deleted the local copy off their phone individually, folks who had uninstalled the app (thus deleting all local data), etc. and has been an ongoing sore spot. When making panoramas in ICE or Photoshop to upload to our account, we retain access to the input images and also have the ability to save a local copy, but with Photosynth's mobile panorama apps this is not the case.
So what is planned for SynthExport as far as panos go is to just download the cube faces + then stitch them in ICE locally to give one a local copy.