“Sad Panda” as Paul refers to it. Presto won’t make it to F11. It’s sad because it saves a lot of time and bandwidth since it only downloads the change in the packages and not the entire package.
More info from Paul’s post here :: http://paul.frields.org/?p=1611
How does Presto work? Yes, good question.. The following articles should solve most of your queries. For more, please ask 🙂