If you are using CDN you may have a separate host for it (eg cdn.yoursite.com), and the original site URL should be replaced with it.
You can specify a different hostname for SSL version of the page, however it is a legacy feature, for a properly configured website you won’t need this.
By default Swift Performance will use CDN for the following file types:
If you would like to use CDN for custom file types, you can specify it one-by-one. Use the extension (eg pdf) without the leading dot.
You can also exclude specific file types on the same way as you can include custom ones: specify file extensions one by one, (eg: pdf)