All CDK classes should have JavaDoc, and as part of that a @cdk.githash tag, so that our build system can add links to the JavaDoc HTML to the source code.
Missing @cdk.githash tags are reported by OpenJavaDocCheck, which reports you can find here:
JavaDoc with a @cdk.githash should look something like:
* Implements the idea of an element in the periodic table.
* @cdk.module silent