This is a background event then inserted into "Second"

This event has the “event_start” label attribute which is defined in the widget as the tag marking events to be fetched.

This event has the “event_end” label attribute which, combined with “event_start”, makes this event a “range” event showing in a limited box between the start and end dates.

This event has the “event_type” label of value “background”, sorting it into the corresponding group with id “background” defined in “event_type_list” attribute on the widget, but then the event is forced into the group “second” as defined. The group “background” never appears on the timeline or as a button, it is a way of sorting specific events as “background” events (showing in the background of the timeline, commonly used for eras/epochs or large stretches of time) within an existing non-background group.