But cygwin seems to have v7.1 too. Is it "just" a build that doesn't depend on cygwin.dll? (Although I can appreciate that's probably a nontrivial porting job). Genuinely curious about what's new here.
It's an early alpha build. This is "just" getting to a point where they're working on a modern codebase. MS has said that they're going to add more functionality as they develop this into a much more useful admin tool.