Related information
The Custom fields section of the History tab of a rule form displays a list of name-value pairs, or custom fields, associated with this rule. This section appears for Rule- objects only. You can add, modify, and remove custom fields in this section. ext (string) and File (rule file binary) custom field types are supported.
Before you start, ensure that the rule is unlocked and accessed from a supported browser version of Internet Explorer.
To find rules with custom fields defined, run the Find Rules by Custom Field wizard.