Calendar Sync Utility is a small, private macOS application that copies a user's own Google Calendar events into a calendar in Apple Calendar on that user's computer, so their schedule is visible in one place.
It is personal-use software operated by its developer for a small number of known individuals. It is not offered to the public, has no commercial purpose, and is not available for download here.
The application reads calendar data only with the account holder's explicit consent, and only with read-only access. See the privacy policy and terms of service for details.