The domain https://fediverse.observer/ redirects to sedo now.
On October 11th these two commits where made to the repo:
this will be my final release, glad to have contributed since 2011 to some fediverse stats, https://fedidb.com/ is a great resource with more interest
this software is no longer developed
Sad to have lost such a great resource.
I remember when he changed the metric on which fediverse software were ranked, just so that pixelfed rises up and rank or two !