How do I add additional columns to Convert Lead page that shows existing Contacts that might match?

How do I add additional columns to the page that says:

The contact record you are about to create might be a duplicate of an contact record that already exists. Contacts records containing similar names are listed below.
Click Create Contacts to continue creating this new contact, or select an existing contact listed below.
This page appears when trying to convert leads to contacts.

In addition to the correct answer.

The following needs to be done to complete the column labels:

In file ./custom/modules/Leads/language/en_us.lang.php there is an array of $mod_strings.  The following needs to be added for each column.

Database field name(or alias given in query) = {field name}, example: primary_address_city.

'db_{field name}' => 'LBL_LIST_{FIELD NAME}',

'LBL_LIST_{FIELD NAME' => '{label for field name in english',

Example of Primary City:

'db_primary_address_city' => 'LBL_LIST_PRIMARY_ADDRESS_CITY',

'LBL_LIST_PRIMARY_ADDRESS_CITY' => 'City',