Another vote for 7-zip. It is fast, free and easy plus there are no nag screens.
I too am scratching my head over this - I’ve never heard of it either - it looks archaic, and not especially cross-platform. The site mentions a port of it for Mac, but the link doesn’t work (and I suspect they might be talking about pre-OSX)
OK, maybe I was unclear: It’s the most common across the widest array of different operating systems. That’s what I meant.
Well, you would know, I suppose.