It is in the bottom right corner when clicking (i) button just like the https://osmfoundation.org/wiki/Licence/Attribution_Guideline... suggests. The only questionable part I see is that after page reload it flickers for half a second and then gets automatically hidden instead of getting hidden after manual interaction with map. Is there any other point in attribution requirements that it doesn't comply with?

I could've sworn it wasn't there before - but maybe I also just missed it since it is covered by the half-transparent panel (on mobile) and all the other stuff around it distracted me.