I would like to store my contacts/addressbook on my own server.
- open source
- can sync to Android and Thunderbird
- Runs on linux
Nextcloud can do this. See https://apps.nextcloud.com/apps/contacts
It is ready for self-hosting, open source, can sync to Android and Thunderbird and runs on linux.
Docs how to sync with thunderbird are here: https://docs.nextcloud.com/server/13/user_manual/pim/sync_thunderbird.html
You need the thunderbird plugin CardBook.