The Enterprise Vault System Status might sometimes show entries like this relating to backups (or lack of them):
How does Enterprise Vault get this information?
Well the information is stored in SQL system tables, and can be read by anyone – it’s just read by System Status and then made to look nice. Here’s an example of one such script that will give you output showing when databases were backed up:
SELECT sdb.Name AS DatabaseName, COALESCE(CONVERT(VARCHAR(12), MAX(bus.backup_finish_date),101),'-') AS LastBackUpTime FROM sys.sysdatabases sdb LEFT OUTER JOIN msdb.dbo.backupset bus ONbus.database_name = sdb.name GROUP BY sdb.Name