It's a really big download (1.8TB). One where both you and they would be really rather perturbed if the download failed at 90%.

In fact, they'd probably be perturbed by the bandwidth costs even if everyone who wanted the dataset was only downloading it once.

Maybe it uses WebTorrent?

(Not sure why it couldn't just fall back to giving you a .torrent file in that case, though.)

Thankfully, Firefox has the ability to resume broken downloads. As does nearly every other method of downloading, other than (apparently) Chrome.

Broken downloads, yes. Corrupted downloads, no. Given that files served from CDNs are still usually served without HTTPS, there aren't many checksums between the two ends of the pipe to protect it from on-the-wire corruption. Doesn't matter much for video streaming ala Netflix; matters a lot for a structured dataset.

BitTorrent and related protocols handle this automatically by breaking the file into large (megabyte-range) chunks, and then putting the cryptographic hashes of all the chunks in the manifest. As long as you've received the manifest, you can protect against both passive corruption and active MITMing in the same way you resume broken downloads: by just discarding chunks that failed to complete to a state of "has all the bytes and hashes correctly", and trying those chunks again.

(Sadly, HTTP doesn't support a digest response header that applies to each chunk of a "Transfer-Encoding: chunked" response stream, or it could vaguely compete with this. The Content-MD5 header could have done this, but it was removed precisely because implementations were in conflict on whether it was for this, or for hashing the document as a whole.)

Why even fall back? The default for something like this should be a torrent as this is exactly what BitTorrent was supposed to solve!

"only hackers use torrent"

>It's a really big download (1.8TB).

COCO (and friends) provide either cloud-backed rsync tools or curl snippets for this reason.

In this case I agree with you. I was just pointing out that we should be careful with Chrome being used as a "reference".

That part I totally agree with.

I’m really tired of people declaring other browsers “broken“ because they don’t implement the future-of-the-minute that chrome has already added.

FWIW Chrome does have the largest market share of any desktop internet browser. That said, I understand what you are getting at and agree.