Same, another Google product I've never heard of. When I read the headline I assumed it was some PaaS for Scheme. Guess I'll have to make due with Racket on Yandex cloud.
Is this just an acqui-hire?
It was a Slide project I believe. Slide was shuttered a few years ago, along with some gift/pet apps, but Schemer came out the tail end of it and survived for a little bit. It was never promoted or associated with Google much, so there's really no sense in keeping it around.