It's over for Vimperator. While Firefox dropped its old API, Vimperator couldn't survive. I don't know why but it's with a pinch in the heart that I see the closing of the github issue which could have saved it.
There is nothing new. We knew it for more than a year but today is the day. Just with the little red icon notifying the end. The repo will still be there with the code and all to be archived. A testimony of a finished era.
But don't be too sad, it's legacy will remain strong. There is a small community of addons mimicking vimperator which rise from its hashes. Qutebrowser also is gaining some users. So all is not lost. Vimperator is now a fertilizer for a lot of new opensource projects so it's a good news !