All Active Directory (AD) fields on premises can populate data. Fields outside the default AD Schema need special mapping.
Here is a list of fields from AD which are mapped per default:
assistant, c, cn, co, comment, company, department, description, directReports, displayName,
distinguishedName, division, employeeID, facsimileTelephoneNumber, givenName, homeDirectory,
homeDrive, homePhone, homePostalAddress, info, initials, ipPhone, l, mail, manager, middleName, mobile, pager, personalTitle, physicalDeliveryOfficeName, postalCode, postOfficeBox, sAMAccountName, sn, st, street, streetAddress, telephoneNumber, title, url, userPrincipalName, wWWHomePage
Extension attributes (extensionAttribute1, extensionAttribute2 etc) are also supported.
If you want add your own custom fields, you just need to tell Xink the LDAP name of the field and the field gets populated.