Webcal links firefox

Nextcloud version (11.0.2):
Operating system and version (Raspbian jessie):
Apache or nginx version (nginx 1.6.2.5):
PHP version (5.6.29):

The issue you are facing: Every time I open my calendar through firefox it is asking me whether I want to "Add the nextcloud calendar as an application for webcal links. Either I do or I can cancel but then it shows again next time. This was not the case in 10.0.3

I’m not sure what this means and i have tried to find info on this but can’t really find anything that explains whether it is safe to add and what the consequences are or how I can permanently get away with this message from firefox.

See Firefox preferences > applications. You can set the webcal association there (or not.)