What is a watcher?
Task ManagementA watcher is someone kept informed about a task who is not expected to do any of the work.
It is the right role for a manager, or for whoever asked for the work in the first place. They see how it is going without appearing as responsible for it, which keeps the task honest about who actually owns it.
Compare the three roles: the assignee is responsible, a collaborator is working on it too, and a watcher is only watching.