How is it possible??

So, I found a cheater in bullet chess game.
He hasn't been marked by lichess yet, but I am sure pretty soon that will happen too.

But my main question is how can someone cheat in bullet chess, are there some chrome extensions which are allowing this, and does this mean that online platforms will not be good even for bullets now?

This is a disappointing news, I never thought there would be cheaters in bullet chess, but here I am.

How did you know that it was a cheater ?

lichess.org/report

And please don't accuse anyone publicly.