The one I know about1 is the data being sent every 24 hours with a unique ID that they use to count active users. I'm not sure, I mostly do trust they won't do anything weird with this and use Vivaldi sometimes, I guess it's up to you to decide if you want to continue using.
Are you sure about the telemetry? Just watched an interview between the CEO and Techlore. And the CEO said that there is strictly no telemetrics..
The one I know about1 is the data being sent every 24 hours with a unique ID that they use to count active users. I'm not sure, I mostly do trust they won't do anything weird with this and use Vivaldi sometimes, I guess it's up to you to decide if you want to continue using.