I noticed something new that I have not seen in previous versions of DotNetNuke...both, web.config and siteurls.config are backed up to the Config directory. With each change, a folder labeled "Backup_YYYYMMDDTT" is created and a copy of the original files are placed within. I am assuming this is the cached version that gets backed up during the application restart. I have always been careful and made a copy of the web.config file before making the change, but it is nice to know that there is another copy stored in the Config folder just in case. If anyone has any information about how this process works, I would be interested in knowing more details. Please share!