If you aren’t using imgix, it’s recommended that you use some sort of CDN to deliver your media to your end users. If you are using imgix, this setting will be ignored.
CDN Base URL
This is the base URL for your CDN and when Media Cloud rewrites the URL for images, it’ll use this value to replace the default cloud storage host.
Document CDN Base URL
If you want to use a different CDN for non-image files, specify the CDN base URL here.