I'd like to add custom (related to my app) fields to the contact card, for instance, "Message XXXX" or "Call XXXX" on the XXXX contact card irrespective of whether XXXX has an account in my app. As in, my application should append these fields in all contact cards which the user has.
I don't have any information to sync with the contacts in my user's phone, but I want to be able to add those fields in the built-in contact (system app), which begs the question, is there a possible way to do this without having to create account authenticators and sync adapters?
