~411 stars; complements vdirsyncer, khal; Open-protocol CalDAV client (works with Nextcloud, iCloud, Google via CalDAV).
Yes, caldav (python-caldav) is open source under the GPL-3.0 / Apache-2.0 (dual) license.
caldav (python-caldav) is free to use.
Yes, caldav (python-caldav) can be self-hosted (the source is available under the GPL-3.0 / Apache-2.0 (dual) license).
~411 stars; complements vdirsyncer, khal; Open-protocol CalDAV client (works with Nextcloud, iCloud, Google via CalDAV). Auth via basic/app-password/OAuth per server. Open standard — no ToS/ban risk. Dual GPL-3.0/Apache-2.0.