Being a Starter Kit, it helps compile Tailwind and then remove the un-used CSS. It does not matter if you use Tailwind 2 or 3, it should work.

The idea is that Jekyll is Ruby while the way Tailwind is setup (usually) is easier managed by the available NPMs. This kit makes it easy to marry the two.

I like it as this is simpler than the others I had seen, nothing more than the bare needed to get the work done.