Class question

Not sure if this is a Suffusion question or a WP question.

When I use a tool like Firefox > Web Developer > Inspector to analyze a page in my site, I occasionally run into classes like “first-para” for which the class does not appear in the “Rules” panel.

In such cases, how do I locate the class rules for “first-para” so I can see the properties:values for this style?

Is there an explanation for why such classes are not listed in the Rules panel?

Thanks.