The "test-add-alerts" command:

Usage: fossil test-add-alerts [OPTIONS] EVENTID ...

Add one or more events to the pending_alert queue.  Use this
command during testing to force email notifications for specific
events.

EVENTIDs are text.  The first character is 'c', 'f', 't', or 'w'
for check-in, forum, ticket, or wiki.  The remaining text is a
integer that references the EVENT.OBJID value for the event.
Run /timeline?showid to see these OBJID values.

Options:

   --backoffice        Run alert_backoffice() after all alerts have
                       been added.  This will cause the alerts to be
                       sent out with the SENDALERT_TRACE option.

   --debug             Like --backoffice, but add the SENDALERT_STDOUT
                       so that emails are printed to standard output
                       rather than being sent.

   --digest            Process emails using SENDALERT_DIGEST