A file should exist called cert.sh (which is ignored for this repo by the file .gitignore) which contains a single line:
export cert="Developer ID Application: CERTIFICATE_NAME"
Where CERTIFICATE_NAME is something like University Corporation for Atmospheric Research (__KEY__)
Run create.sh ${cave_export_directory} to prepare the directory awips2-cave-template
Run dmg.sh to create a signed DMG for distribution from awips2-cave-template