DWP

What does the number 2 in the top right corner of the call log phone icon mean? I marked it with red circle and arrow. Why is it always 2?

Thanks.

Hello everybody! I would like to set my sms app to dark theme. I set it, it is black now, still if I go to a certain chat, it appears in white, not in black. How can I set every chat to black? THX for the answer.