From In-Portal User Manual

This tab controls module-specific category properties. The contents of the tab depends on the modules installed.
In-newz module adds the following properties: RSS Feed Properties:

• Source URL – this fields controls the RSS source URL used for populating current category with articles. The field also accepts multiple RSS source URLs separated by commas.
• Update Interval – the time interval used for parsing the RSS source and populating the category with articles.

RSS Feed Articles Expiration

• Default Expiration – the default expiration time of articles imported through RSS into the category.
• Expiration Check Interval – the time interval controlling the frequency of checking the expired articles for the purpose of deleting it (see Delete Expired checkbox below)
• Delete Expired – the checkbox controls whether expired articles should be completely deleted from the system, or simply marked as archived (expired).

As of the current version, In-link, In-commerce and In-bulletin modules do not have any category-level properties.