Activity History of a Record
How BackOps records what happened to a record, who did it, and when, and where the history panel appears today.
Activity history answers "what happened to this, and who did it?" For a record that has history, BackOps keeps a list of entries, newest first, and each entry says what happened, who did it, and when. It is separate from notifications: notifications alert people as things happen, while history is the record you read afterward.
Where History Appears Today
History is shown in a panel on resource need sheets in the organization's resource coverage view. It is not on every record yet, so a record without a panel has no history shown in the app.
Reading It Through the API
The same history is available through the Notifications API for any record that records it, by the record's type and id. Reading it needs access to the organization and, when you narrow to one event, to that event. See get history.