Beta 2 is no longer available on RME website(returns 404 if I try link from old thread in another forum, was working before)
You may try this one, but I don't know if it's compatible:
A new BETA version of Remere's Map Editor 3.0 is available! - Page 7
will be for 9.81 when Remere release his mapeditor
if he won't I'll start work on these extensions when I finish my evo datapack
It doesn't work for me. I add all into extractions folder, run rme and nothing.