Not sure about that but I did implement it in my website and here are the screenshot of how they work on the same Firefox Android browser. 

On FrankieGPT I request an event signature, user is presented and "ACCEPT" button and after that my webapp will receive the signed event, including the public key and there's no need for further interaction or special permissions that I know (or remember) about. 


https://m.primal.net/HwmD.jpg https://m.primal.net/Hwlz.jpg