Standard alert
Machine name: alert
The node is either referenced to to an app (og_group_ref_single) or to a group or private group (og_group_ref_groups) this is through an organic group entity reference field type.
The alert visibility is set as private which means the user must be a member of that group (apps are groups too) to view it.
There is a date field for the date time to send (field_schedule_sending)
When a new alert is added it is unpublished.