The Events Calendar – Show ics export link on single events

tribe_activate_ics_export_on_single_events.php

<?php
/* Classic Editor: Activate ics links */
add_filter( 'tec_views_v2_subscribe_link_ics_visibility', '__return_true', 20 );

/* Classic Editor: Make ics link first item in dropdown */
add_filter( 'tec_views_v2_subscribe_links', function ($links) {
  if (isset($links['ics']) && is_singular( 'tribe_events' )) {
    $links = array_merge(['ics' => $links['ics']], $links);
  }

  return $links;
} );

/* Block Editor: Activate ics links */
function custom_add_ical_link($output) {
  if (function_exists('tribe_get_single_ical_link')) {
    $ul_class = 'tribe-events-c-subscribe-dropdown__list';
    $li_class = 'tribe-events-c-subscribe-dropdown__list-item';
    $a_class = 'tribe-events-c-subscribe-dropdown__list-item-link';
    
    if (strpos($output, '<ul class="' . $ul_class . '">') ) {
      $split_output = explode('<ul class="' . $ul_class . '">', $output);
      $output = $split_output[0];
      $output .= '<ul class="' . $ul_class . '"><li class="' . $li_class . '"><a href="' . tribe_get_single_ical_link() . '" class="' . $a_class . '" target="_blank" rel="noopener noreferrer nofollow noindex">' . __('Export .ics') . '</a></li>';
      $output .= $split_output[1];
    }
  }
  
  return $output;
}
add_filter( 'tribe_template_html:events/blocks/parts/subscribe-list', 'custom_add_ical_link' );