As pointed out but Thorsten "would you trust a java library or tools that had 0 javadocs" - it may make sense to use js docs to document important modules, methods or public apis.

This could yield documentation similar to what the ATH has, served by github here: https://jenkinsci.github.io/blueocean-acceptance-test/page_objects.module_folderCreate.html
https://jenkinsci.github.io/blueocean-acceptance-test/index.html

source: https://github.com/jenkinsci/blueocean-acceptance-test/blob/master/src/main/js/page_objects/classic_jenkins/folderCreate.js

In scope:

• documentation in comments for important modules
• Generation of HTML docs from these comments and publishing