I have no idea. I'm not sure what you were looking at.

If you visit just "https://noto-website.storage.googleapis.com/", that's a request to list all of the objects in the bucket, so you'll see an XML document with that namespace and the results of a listing.

If you were trying to download a specific object from that bucket, you'd either see the resource itself, or you'd see an XML error result of some sort (404, 403, etc). So I assume that either you mistyped the object name once or else the object had been deleted for some reason.