From Luther B. Fuller:
Script Bundle Tool creates an application bundle from an editable AppleScript source file and a contents folder. When you first use Script Bundle Tool, the contents folder is created automatically and you set the properties: Version, Copyright, Stay Open and Show in Dock. Subsequently, you need only to Select, Launch and Click to create a new build of your application bundle. The source file may be any editable AppleScript application or script document created with Smile or AppleScript Editor. When you build an application bundle, AppleScript Editor creates a new application bundle, then the sub-folders of the project's contents folder are copied into the new bundle's Contents folder and any custom keys in the project.plist file, are written to the new bundle's Info.plist file. A locked and dated copy of the source file is copied to the versions folder, if present.