Archive.org does this with theirs. If there are no seeds (super common with their torrents—IDK, maybe a few popular files of theirs do have lots of seeds and that saves them a lot of bandwidth, but sometimes I wonder why they bother) then it'll basically do the same thing as downloading from their website. I've seen it called a "web seed". Only place I've seen use it, but evidently the functionality is there.

I'm pretty much convinced the people at Docker have explicitly made their "registry" not be just downloadable static files purely to enable the rent-seeking behavior we are seeing here...