For privacy reasons, it's kept out of Cloudflare's cache. But one could argue that it doesn't matter since traffic is flowing through Cloudflare anyways. What do you think?
From their terms: (emphasis mine)
> Unless you are an Enterprise customer, Cloudflare offers specific Paid Services (e.g., the Developer Platform, Images, and Stream) that you must use in order to serve video and other large files via the CDN. Cloudflare reserves the right to disable or limit your access to or use of the CDN, or to limit your End Users’ access to certain of your resources through the CDN, if you use or are suspected of using the CDN without such Paid Services to serve video or a disproportionate percentage of pictures, audio files, or other large files. We will use reasonable efforts to provide you with notice of such action.
https://www.cloudflare.com/service-specific-terms-applicatio...