Update docs/api-reference/next.config.js/custom-page-extensions.md

Co-authored-by: Matthew Francis Brunetti <zenflow87@gmail.com>

docs/api-reference/next.config.js/custom-page-extensions.md

@@ -34,7 +34,7 @@ Then rename your pages to have a file extension that includes `.page` (ex. renam
 
 > **Note**: As mentioned in the note above, make sure you also rename `_document.js`, `_app.js` as well as files under `pages/api/`.
 
-Without this config, when building the production bundle, Next.js will throw an error like this if there are non component files in the `pages` directory:
+Without this config, Next.js assumes every tsx/ts/jsx/js file in the `pages` directory is a page or API route, and may expose unintended routes vulnerable to denial of service attacks, or throw an error like the following when building the production bundle:
 
 ```
 Build error occurred