The roster tool display's info about the user which is then sometimes exported. Many institutions publish SIS data as user properties and they would like the ability to see those SIS properties in the roster view and also include them in the export.
In the implementation the roster tool controls the view of columns using permissions. So a new permission was added for the "User Properties" column, "roster.viewuserproperties". The permission is off by default until decided otherwise.
Also a sakai property "roster_view_user_properties" was added to provide the ability to completely turn this off, however it is enabled by default. Though when enabled it still can be controlled via the tool permission mentioned above.
To retroactively add this perm would suggest using the admin perms tool.