Dux Calendar
Dux Calendar is a free, open-source desktop calendar application for Linux and FreeBSD. It lets users connect their Google Calendar and Google Tasks accounts to view, create, update, delete, and synchronize their own calendar events and tasks. It also supports Local, Microsoft, CalDAV, and iCloud calendars in the same unified agenda.
Dux Calendar uses Google account data only to provide the calendar and task features requested by the user. The application runs locally, has no hosted backend, and stores calendar data and OAuth credentials on the user's device.
How Dux Calendar uses Google user data
When a user connects a Google account, Dux Calendar accesses the user's calendar events and task lists through the Google Calendar and Google Tasks APIs to display and synchronize them in the app, and the account's email address to identify the connected account. All data stays on the user's device: nothing is transmitted to the developer or any third party. See the Privacy Policy for details, including how to revoke access.
Free and open source
Dux Calendar is released under the MIT License and developed by Dux Labs. The command-line executable is named dcal.