This is perfectly timed, as I wanted to find a way to programmatically modify my Mac's AppleScript display settings/theme. For whatever reason, they're stored as typedstream format, embedded in a plist in base64. Found an old implementation/header from 1999 from Mac OS X Server v1.2, signed by Bertrand Serlet, and was going to dig in when I found the time. Now I can dig into this.