@ebel I'm working on such a thing right now for [async-fetcher]. I haven't released it yet, but there will be a `fetcher` CLI binary based on this that receives URLs from standard input, and gives back stats on its fetching on standard output. It won't fetch files which it has already downloaded, and it will support validating checksums.
I will personally be using this in Pop!_OS for fetching debian packages and source lists from apt repositories.
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