Customer master link
This will display a Yes or No based on whether or not you have a customer master link with the client. Only tax agents can have a customer link and you must have Full authority to act for all tax and social policy to link at this level. This allows you to take actions at the customer level, such as an overall change of address or viewing Customer level mail.
Accounts (tax types)
This will display a 1 for each account you are linked to. Hovering over the abbreviations will tell you the full name for each account.
Latest account link date
This will display the date of the latest link made for the client.