Zebras. (I just wanted to use my "z" illumination.) In general, it's not necessary to add a timezone to both start and end dates. But if you modify the date format, that's exactly what will happen. So how do we add the site timezone just to the end of the DateTimeRange? The solution uses mytheme_preprocess_field() to append the timezone abbreviation to the end date, producing output like: 8/2/17 5:15 PM - 8/2/17 10:15 PM EDT…
Read more about Append Site Timezone to End Date in DateRange in Drupal 8
