The tasks are located in the Change Objects --> Process --> Tasks for Change Process --> Related Tasks
or in the Context --> Tasks.
Reason why others have the need to see the details of such tasks:
An assignee of an "Validation Error Task" ignored the validation errors. This produced sometimes problems in the following workflow steps and generates other "error workflow tasks". But the assignees of the following tasks can´t see why the validation errors which were ignored before because they are not assignees of the previous tasks / or no admins. So they have always to ask the previous assignees about the details of the validation...