Does Google App Engine keep code snapshots of past deployments?
You can only see which version of your app was deployed and when - unless you deleted the older version.
I've deployed code changes to a GAE app under development and broken the app.  My IDE isn't tracking history to the point in time where things still worked, and I didn't commit my code to a repo as often as I updated the app, so I can't be sure what the state of the deployed code was at the point in time when it was working, though I do know a date when it was working.  Is there a way to either:

Rollback the app to a specific date?
See what code was deployed at a specific deployment or date?

I see that deployments are logged - I'm hoping that GAE keeps a copy of code for each deployment allowing me to at least see the code or diffs.