The package name throughout all files is 'spinhead', one of the other form fields, rather than 'diyogi', the theme name I chose.
The downloaded zip file of the theme was named for one of the other fields, not the theme.
It's confusing, and combined with the unexpected automatic download when a user clicks the Generate My Theme button, could easily result in someone never realizing the theme had been successfully generated since no file bearing the theme name is created.