in case calender entries do not have an end_time, e.g. the end_time ist the same as the start_time, the following code extension will improve the agenda view of the calendar, such that the time will not be written like
9:00 - 9:00
which is fine for an entry with open or unspecified end.
If the end_date is different from the start_date but the start/end_time is equal, nothing will be changed.
If it's fine for you feel free to add it to the official code.
> diff app/view/agenda.php app/view/agenda.php.orig
< <?php echo esc_html( $event->start_time ) ?>
< <?php if( ($event->start_time != $event->end_time) || ($event->short_end_date != $event->short_start_date) ): ?>
< <?php echo esc_html(' – ' . $event->end_time ) ?>
< <?php endif ?></span>
> <?php echo esc_html( $event->start_time . ' – ' . $event->end_time ) ?></span>