The Process Definition Details has been considerably dumbed down in 6.3. Whereas in previous versions it showed (in my opinion very valuable) information like proc. variables (+their type), users/groups/human tasks declared in the process etc, now it only shows Process ID, name and deployment id.

I think this simplification is not acceptable and more details should be brought back. I found that the client classes with more details exist in the console sources [1], but I didn't find a way to access them in the UI. Please bring more details back.
[1] https://github.com/droolsjbpm/jbpm-console-ng/blob/f8acd96604c7dd44ba79b120086ed6ac18b6dede/jbpm-console-ng-process-runtime/jbpm-console-ng-process-runtime-client/src/main/java/org/jbpm/console/ng/pr/client/editors/definition/details/advance/AdvancedViewProcessDefDetailsPresenter.java