Clojure is a popular functional Lisp dialect that's hosted on the JVM, and leverages Maven artifact repositories for package management and deployment. While some Clojure projects are deployed to Maven Central (notably the core language itself), Clojars has become the de-facto standard artifact repository for most community-developed Clojure open source projects. At the time of writing Clojars hosts approximately 32,000 unique projects (as defined by groupId+artifactId), totaling almost 300,000 distinct artifacts (i.e. groupId+artifactId+version).

Clojars is a well-managed, secure, and fully Maven-compatible artifact repository, and so it is my belief that it meets ClearlyDefined's criteria for consideration as a new provider.

More generally, there are other widely used Maven artifact repositories that may also be of interest to other JVM developers as ClearlyDefined providers. mvnrepository.com's repository index is a good place to get a better sense of the broader Maven ecosystem and how it is used by JVM developers (especially those who aren't restricted to Java-the-language and/or Maven Central).