Here's what I'm seeing so far:
The whole framework is touched by the OTA. The core of the framework itself has had a significant patch applied.
Every system application is touched by the OTA, but the focus seems to be on the Market, and the stock email (not Gmail) client.
When you update, you get an older version of the Market, but with a newer version of the vending.odex file. When you first connect to the market, you silently update to the latest version.
The recovery is touched by the OTA.
I'm not seeing anything visibly different, other than losing root in the stock FRG83 ROM. The apps and framework (and probably the recovery, too) were probably just patched to mark them as a newer version. I imagine this is all in preparation for the Market changes that are coming overnight, but there is a good chance that you will need to apply this OTA in order to get the next one, as it does touch the recovery.
Anyone seeing anything I might have missed?