As usual, the AmigaBest site causes more problems than it solves. STAY AWAY FROM IT!! (Seriously, it's a perfect example of the sort of semi-legal download site that should be eradicated)
The kernels in question are test kernels, specially the Eden one. The person doing them is indeed trying to add support for more hardware, and he is on all the Amithlon lists, but these are not even "unofficial" releases, and should not have been made available for download on a public site.
If AmigaBest didn't completely ignore licensing terms, you should be able to find the kernel sources there too.