Moth-Light is definitely still in active development, though it will probably be a while till it is finished and turned into a full-sized book.
The good news is that the game itself is more playable and more unique, as a game, than it ever has been! If you haven’t checked it out in a while, definitely give the new rules a look.
The next update will be focusing on editing the games text and making it clearer and pleasant to read. Expect that sometime in the next few months!