It makes me very curious.
Delivered to GitHub fully-formed: A grand total of 9 commits (mostly docs and CI fixes), all in the last 5 hours, and v0.1.0 released 3 hours ago.
No external database/storage-layer dependencies, so it's not "just" a CLI/server/parser wrapper around other libraries doing the "real work".
It appears to have a substantial test suite (76% code coverage, not skipping the scary bits), and great documentation.
There's a bit of context on https://github.com/stoolap but not much else about the author, project goals, relationship to other systems, e.g. it could be the data layer for something else.
(Interestingly, there's an archived stoolap-go repo with a very similar Go implementation of a columnar/hybrid database, so this is not the author's "first draft".)