Adds a column to the registrations CSV in Event Espresso 4 to display the name of the event's venue

add_venue_to_reports.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_filter(
	'FHEE__EventEspressoBatchRequest__JobHandlers__RegistrationsReport__reg_csv_array',
	'espresso_add_venue_to_report',
	10,
	2
);
function espresso_add_venue_to_report( $reg_csv_array, $reg_row ) {
	$event_id = $reg_row['Registration.EVT_ID'];
	$event = EEM_Event::instance()->get_one_by_ID( $event_id );
	if ( $event instanceof EE_Event ) {
		$venue = $event->get_first_related( 'Venue' );
		if ( $venue instanceof EE_Venue ) {
			$venue_name = !empty( $venue ) ? $venue->name() : '';
			$reg_csv_array['Venue'] = $venue_name;
		}
	}
	return $reg_csv_array;
}