Although niche, things are pretty lively in the community. Among other things this year great progress was made on Jank, the native LLVM-based implementation with seamless low-level C++ interop. As part of that work a test suite is being created [0] and now includes runners for all of the major implementations to compare compatibility, next best thing besides a formal specification.

[0] https://github.com/jank-lang/clojure-test-suite