BRBACKUP, BRARCHIVE, and BRRESTORE Logs 
Logs are created when calling the SAP programs BRBACKUP, BRARCHIVE or BRRESTORE. These are a source of information about performed operations and are particularly useful for error analysis.
They are also a prerequisite for the smooth execution of the operations that you can perform using the SAP programs (for example, for the restore and recovery process).

You should always include logs in a problem message to provide a basis for error analysis.