DirectoryStorage keepclass feature
DirectoryStorage supports classes that need to keep their history longer than normal. This is useful if you want to keep all revisions of a class for auditing purposes, or because you want to view extra history of a class using a Zope history tab.
Class names are registered in the [keepclass] section of the config file, together with a specification of how much extra time they should be kept. The following examples keep an extra week of history for Zope DTML Methods never discard history for DTML Documents. This feature is of more use with application-specific class, and not particularly useful for these standard document classes.
[keepclass] OFS.DTMLMethod.DTMLMethod = extra 7 OFS.DTMLMethod.DTMLDocument = forever