I`m using NextCloud and i figured it out using the following config
{ module: "calendar", header: "username", position: "top_left", config: { calendars: [ { symbol: "calendar-check-o ", url: "https://username:app_password@nexctcloud.domain.nl/remote.php/dav/calendars/username/8a757113-03ae-4d7a-a6a1-8db4350eee54_shared_by_username?export" } ] } },I got the calander name from the webinterface by clicking on the dots right behind the specific calender.
Note: I am using a dedicated user to login to nextcloud. This user is recieving the “shared” calanders from the actual users. In this way i don`t need to login with my own nextcloud credentials