This is a detailed list of other requesters with access to the same information. You'll see a red Unverified if they haven't yet shown they control their email account by entering a verification code. You'll see a red Unauthorized if they aren't on the authorized email address list.
By clicking on the ID number in the View column you can either email the person for contact or inactivate their account preventing them from further access.
An agency can isolating team members to specific locations for your customer account. If a user has Access To All Locations then they are essentially administrators and can inactivate other requesters and create/edit locations. The location column will show which locations a requester has been granted access to see, they'll only see appointments associated to those locations.