Filters can be added to control what feeds get sent to Discord via the command filters. There are five categories for which filters can be applied to: title, description, summary, author and tag.
Categories are set by the feed author, and not by you. Setting a filter to a category that does not exist or is not identified by the test command will cause all articles of the feed to fail the filter.
There are two types of filters: regular or regex. If regex filters are defined, regular filters will be ignored.

Filters on Other Article/XML Properties

You can apply filters to non-standard raw properties. Use the dump command, find the relevant name, and use raw:<name> as the filter category (replacing <name> with the name in the dump output).