By checking project's structure, I can see that until branch 5.3.x, maven and gradle are available as build tools.
Starting from branch 6.x this is not the case. There is not a pom.xml which in my understanding means that maven is not supported anymore as build tool.
However, on the official docs, for example for delegated authentication , dependency is also available as maven artifact(Maven tab).
So what is really happening? Is maven deprecated as build tool for the overlay?
From the release notes published almost a year ago at:
https://apereo.github.io/2018/09/14/600rc2-release/#war-overlay
The Maven WAR overlay template is now deprecated and moved aside. The reference overlay project simply is transformed to use the Gradle build tool instead. This is done to reduce maintenance overhead and simplify the deployment strategy while allowing future attempts to make auto-generation of the overlay as comfortable as possible.
The maven dependency tab exists because:
In theory there is nothing stopping you from creating your own overlay using Apache Maven and using one of those dependencies in your own project on your own.
A Maven dependency is not only used for a CAS overlay project; it can be used as an external dependency in any other projects for extensions or add-ons all of which may be based on Apache Maven.