Upgrade to Fedora 13 from Fedora 12
 

When you upgrade from Fedora 12 to Fedora 13, using Preupgrade, where does Fedora 12 put the upgrade file (Temporary file) and what does it call it?

Yum usually works by checking which Fedora release version is installed. I would imagine that the preupgrade package downloads and installs the new fedora-release package for you. A yum upgrade command is then run which upgrades all F12 software to F13. This is an automatic way of doing what we had to do manually before the preupgrade package was introduced.
Here's a historical document showing the old way of doing it.

The upgrade file is called preupgrade.

So when you run preupgrade, the preupgrade package downloads fedora-release and both would be stored under /var/cache/yum/i386/12/fedora/packages on a 32 bit machine.

Whether they will be there after the upgrade is questionable as I expect it runs yum clean all when it has finished. This removes all temporary packages.

preupgrade uses the space in /boot
that is one of the reasons that it went from 78 meg ( min) recommended 100 meg to the VERY large 800 meg

if you intend on using " preupgrade" i would recommend you set /boot to about 1.5 gig .So that there is space for the needed files.