tw_ee_csv_always_add_event_name.php

<?php //Do not include the opening PHP tag if you already have one.

add_filter(
    'FHEE__EventEspressoBatchRequest__JobHandlers__RegistrationsReport__reg_csv_array',
    'tw_ee_csv_always_add_event_name',
    20,
    2
);
function tw_ee_csv_always_add_event_name(
    array $csv_row,
    $reg_row
) {
	$event_model   = EEM_Event::instance();
	$reg = EEM_Registration::instance()->get_one_by_ID($reg_row['Registration.REG_ID']);
	
	$event_name[esc_html__('Event', 'event_espresso')] = sprintf(
		/* translators: 1: event name, 2: event ID */
		esc_html__('%1$s (%2$s)', 'event_espresso'),
		EEH_Export::prepare_value_from_db_for_display(
			$event_model,
			'EVT_name',
			$reg->event_name()
		),
		$reg->event_ID()
	);
	$csv_row = EEH_Array::insert_into_array(
        $csv_row,
        $event_name,
        'Registration ID',
        false
    );
    return $csv_row;
}