Workflow viewer displays information needed for a workflow or a draft workflow, (optional) associated to a given project. To get access to the workflow viewer, you must have Administrator permissions.
Go to Jira Administration > Add-ons > Workflow Viewer.
You can select a Jira project to see the associated workflows, including draft workflows (if any), for each issue type associated or you can select the workflows or draft workflows directly to view information about them.
The report looks like this:
At the end of the report you can find the additional information about the validators, conditions, and post functions present in the Edit or View screens included in the issue screen scheme, associated to the current issue type.
If there is no project selected for a workflow viewer, then there will be no associated issue type to a given workflow. So there will be no such issue screen scheme associated and the information about the edit or view screen will be missing.