Is there a complete documentation for tm4j / com.kanoah.test-manager / TestCasePublicService, ...?

Is there some complete documentation how the services work? 

https://scriptrunner.adaptavist.com/5.3.9/jira/plugins/working-with-tm4j.html does provide some examples but does not explain hardly anything.

description of library methods com.kanoah.testmanager