The audit_binfile plugin creates binary audit files. Each binary audit file is a self-contained collection of records. The file's name identifies the time span during which the records were generated and the system that generated them. The time stamps that indicate the time span are specified in Coordinated Universal Time (UTC) to ensure that they sort in proper order, even across time zones.
For more information, see the audit.log(5) man page. For examples of open and closed audit file names, see How to Clean Up a not_terminated Audit File.