The Audit tab displays a complete audit trail of all changes to the main entity record since it was first created. The Current Instance view is the record as it currently stands in the database. The revisions are then a reverse chronological display of each change made to the record, the individual values which have changed are highlighted in red as shown below.

Audit data for Comments and non top level entities as described above is not shown here, this is accessed by right clicking rows on the relevant tabs.