Mittens...
That incarnation of a demon.
Is the Mittens bot Stockfish?

I am 2300 and have been playing against this computer. So far I have a plus score of 6-5.
That's a really bad score if you're playing 1|0... because you should win every game easily.
If you play it for real you'll probably lose. Hikaru drew it in a game that lasted 30 minutes. When I played it against stockfish about half of its moves were less than best, so I think a strong GM might beat it in a long time control game... but not you
I am 2300 and have been playing against this computer. So far I have a plus score of 6-5. It's eye's colour looks like the colours of the design of Stockfish.