Is there some documentation somewhere about the Kaocha CircleCI orb?
not really, what do you want to know?
the source is here: https://github.com/lambdaisland/meta/blob/master/circleci/kaocha_orb.yml
it's something I never got around to polishing up and announcing publicly
there's also a generic clojure orb https://github.com/lambdaisland/meta/blob/master/circleci/clojure_orb.yml
which uses docker images created with Nextjournal https://nextjournal.com/plexus/openjdk11-%252B-clojure/edit