I presented An Introduction to Configuration Management at the first-ever Flyover Camp in Kansas City, MO. Below is an Apple keynote file and PDF with presenter notes as reference.
config_override_warn - If config is overridden in settings.php it will let you know if you try to change it in the UI.
config_readonly - Adds settings.php config to lock down config changes from the UI.
config_split - Alternate config for specific environments