You can see what Web Filter Category a website falls into by going to Apps > Web Filter > Site Lookup. Enter the website there and click the Search button.
Correcting miscategorized URLs
If you feel that the website is miscategorized, you can submit a recategorization request after your results are returned (or you can use this tool on BrightCloud's website).
More information about BrightCloud® Categories
To see more details about what each Category contains, visit this page on their website and click Web Category Descriptions.