event-tickets-attendee-wp-list-extra-col.php

<?php
### Example of adding an extra column to the Event Tickets/Event Tickets Plus
### attendee table.
###
### Tested with Event Tickets Plus 4.6.2

# Register our extra column
add_filter( 'tribe_tickets_attendee_table_columns', function( $columns ) {
	$columns['extra'] = 'My extra column';
	return $columns;
} );

# Populate the extra column ($item can be used to identify the actual attendee object)
add_filter( 'tribe_events_tickets_attendees_table_column', function( $val, $item, $column ) {
	static $count = 0;

	if ( 'extra' === $column ) {
		$val = 'Extra column value ' . ++$count;
	}

	return $val;
}, 10, 3 );

Thank's a lot!!!! Super helpfull 👏👏👏

Thanks for the note (happy to hear this still works some 4 years later)!