These settings are actual for Start steps only and specifies  person(s) who can manage steps of a current process instance ("instance managers"). The difference between them and Process managers is that instance manager remains the same for the started instance even if it has been changed in the process. Also, instance manager(s) are set in "Manage" section of step on Progress bar:

Settings are:

• Manager Type (1) - select the type of Manager (user, role, profile, etc).
• Value (2) - select a person/role/group/etc. to set as manager.