Where does scutil store its information?
scutil talks to the System Configuration daemon, configd. Some of the info it deals with isn't stored anywhere (except in RAM), because it relates to the live state of the computer. The part that does get stored is (at least mostly) in the /Library/Preferences/SystemConfiguration/ directory, especially the preferences.plist and NetworkInterfaces.plist files. man scutil and man configd both have relevant (if superficial) info.
The format of the information in the configuration database is rather cryptic, both when viewed directly in the files and via scutil. For most network configuration tasks, networksetup is much easier to work with. I don't really recommend using scutil except for its --set and --get options (which set and get the Mac's various network names). What are you actually trying to do?