Right. As I mentioned, you're just moving the signature from the blob itself to HTTPS, and if all you care about is validating a file you'd just make that a hash. Analogously to a SHASUM file, but the authentication coming from HTTPS/WebPKI instead of something ending in .asc.
One critical point is that the two servers do not have to be the same. You might distribute your files via a CDN like CloudFront (or if you're in the 90s and a Linux distribution, a ragtag team of servers that don't generally implement https). The server responsible for delivery can lie all it wants; the server responding if something is valid is what actually matters.
One critical point is that the two servers do not have to be the same. You might distribute your files via a CDN like CloudFront (or if you're in the 90s and a Linux distribution, a ragtag team of servers that don't generally implement https). The server responsible for delivery can lie all it wants; the server responding if something is valid is what actually matters.