You can view all restricted pages in a space: Confluence Page Restrictions > View all restricted pages in a space
However, keep in mind that you wouldn't need to specifically permit anonymous writing unless you allowed anonymous writing in the Confluence Global Permissions, so there's a chance that won't show up there.
If you're not on Confluence Cloud, another option would be to try a User Macro to display all restricted pages in the entire wiki, such as the one developed by a user here. Keep in mind that particular one was written in 2013 so it may not work for your current version of Confluence.
Let us know if you have any trouble.
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