1. Adobe Experience League - Campaign Classic v7 Documentation
"Target mapping": "The Target mapping link lets you link the data from a temporary workflow table to the data in the delivery logs. [...] You can store additional data in the logs. To do this
select the Keep this data in the broad log option." (This section explicitly details the function of mapping workflow data to the broad log).
2. Adobe Experience League - Campaign Classic v7 Documentation
"Enriching delivery content": In the section describing how to add personalization fields from a workflow
the documentation states: "In the Target mapping tab of the delivery properties
you can specify where the additional data is stored. By default
it is not stored. If you want to keep it
for example to use it in other messages
select the Keep this data in the broad log option." (This provides a use-case and confirms the configuration location).