I don't know. I believe she is called Vivian James and that she is from 4chan or 8chan and she is supposed to be a gamer girl. She has something to do with Gamergate, I suppose :T
Basically she is anti-SJW and just wants to play games in peace without it being turned into political drama.
Pretty much a mascot yes.
Although this is only what I have been able to gather as I am not a 4chaner/8chaner. I just really liked the avatar, thought it was pretty cute.