Adds the event location to the EE4 calendar event. Requires EE4.

add_location_to_calendar_event.php

function jv_ee_add_location_to_calendar_event( $text, $datetime, $event ) {
    if ( $event instanceof EE_Event ) {
        $venue = $event->get_first_related( 'Venue' );
        if ( $venue instanceof EE_Venue ) {
            $venue_name = $venue->name();
            $text .= '<span>Location: ' . $venue_name . '</span>';
        }
    }
    return $text; 
}
add_filter( 'FHEE__EE_Calendar__get_calendar_events__event_time_html', 'jv_ee_add_location_to_calendar_event', 10, 3 );