The default trace is part of a standard SQL Server installation and usually runs silently in the background, writing its contents to .trc files.
These files roll over once full so miniDBA will only display data as far back as the files go.
Note - ALTER TRACE server permission is required to view this data.
MiniDBA reads these trace files and breaks down the results into 5 distinct tabs/areas.
The screenshot belows shows the schema modifications tab. It shows all drop, alter & create events for a database that are contained in the .trc files.
The other 4 tabs work in the same way, displaying logically grouped events sorted from newest to oldest.
This is the security tab. It shows all security related modifications for a database that are contained in the .trc files.