I am interested in building my own cards (since there isn't any such card that is currently available..?), similar to this question. However no one answered that question previously.
If not, how else can we achieve deep-linking to open other apps (like for example I want to get directions, I don't mind having to open up Google Maps to do so). But it only seems to work for Android, and it is still in Developer Preview..?
I also want to allow the user to click on a card / a button and call a mobile number, but url only takes in http / https URL schemes and not tel://, so that workaround can't work...