@Dishtron Hayo and MattEsch stopped working on Fishhead 3D, but MattEsch carried on with Stone Goose family of objects (He released even SG level editor or sth like that). But I never heard that extension itself was stopped.
Unfortunately, I've tried contacting him about the Stone Goose objects, but he hasn't responed. Also, MattEsch seems to always be on ClickConverse now, but he doesn't ever seem to say anything or respond to questions, so I'm not sure if he's working on them anymore.