Presumably they can use Cloudflare or similar for free or relatively cheap, or perhaps find someone willing to gift CDN service to a Linux distribution. Redire

Presumably they can use Cloudflare or similar for free or relatively cheap, or perhaps find someone willing to gift CDN service to a Linux distribution. Redirecting the requests to the closest existing mirror also obviously drastically reduces bandwidth requirements and should presumably be doable with a few (for redundancy) colocated dedicated servers running efficient server software.