You have an inbox for each role that you are assigned, so some users will have multiple inboxes. The Author and Doc Lead Project inboxes show all of the objects to which you are assigned the respective role. Inboxes for other roles, including Contributor, Editorial review, Technical review, and Doc lead, show the objects for which you are assigned the respective role and that have been placed in a workflow state that requires your action. For example, if you are assigned a role of Doc Lead for a publication, objects in the Pre-Release Validation state appear in your inbox. After reviewing the objects, you can change their state to Released, and they are removed from your Doc Lead inbox.