9d9b22f4 is another tweak to loading, reversing some earlier decisions. Autoload paths and eager load paths will be separate for Rails 4.0 after all.
c9909db9 drops XML parsing from ActionDispatch. If you need it, you can pick upt he new actionpack-xml_parser gem.
d3688e02 removes the auto-explain option for ActiveRecord. You can still call explicitly ActiveRecord::Relation#explain. I'll miss this, but I know most Rails folks prefer not to think about the database.