The blog post failed to link to their GH repo: https://github.com/Vertispan/j2cl and it's Apache 2 for those like to know: https://github.com/Vertispan/j2cl/blob/rebased_master/LICENS...

Interestingly enough, their M2 repo contains only "-SNAPSHOT" releases, and even those were only published back in 2021. Although there's a commit alleging an actual release: https://github.com/Vertispan/j2cl/commit/482e1592cd84063c16a... which seems to have gone to Central, so it seems best not to use their M2 repo: https://search.maven.org/artifact/com.vertispan.j2cl/j2cl-pa...