code: protected function GenerateAndroidPinicon(SiteConfig $config, SiteTree $owner, &$metadata) {
  
          // header
          $metadata .= $owner->MarkupComment('Android Pinned Icon');
  
          //
          if ($config->fetchAndroidPiniconThemeColor()) {
              $metadata .= $owner->MarkupMeta('theme-color', $config->fetchAndroidPiniconThemeColor());
          }
  
          //
          $metadata .= $owner->MarkupLink('manifest', '/manifest.json');
  
      }
docs: Generates markup for the Android pinicon
  
  @param SiteConfig $config
  @param SiteTree $owner
  @param $metadata
  
  @return void