S.B. suggests that backup generations have an optional description.

1. Named generations -- There are certain generations that are more important than others. Some are automatically created by Obnam itself, some are routinely scheduled, and some were explicitly created. For example, I always run Obam immediately before traveling with my laptop in case it gets stolen or broken. The same goes for backups before major system upgrades. It would be nice to have something approximately analogous to the Windows "restore point" functionality, which has a description field. Sometimes they are only automatically created system checkpoints. But if the user explicitly creates a new restore point, he can add the description "before traveling to Europe" or "before upgrading OS" or whatever. Similarly, the automatic backup script could be programmed to label it as "cron backup".