Issue #3210295: ICS file open in the new tab, now available for download

src/Plugin/Field/FieldFormatter/CalendarDownloadDefaultFormatter.php

@@ -58,6 +58,9 @@ class CalendarDownloadDefaultFormatter extends FormatterBase {
         '#type'  => 'link',
         '#title' => $this->t('iCal Download'),
         '#url'   => $fileUrlObj,
+        '#attributes' => [
+          'download' => $file->label(),
+        ],
       ];
       return $build;
     }