[kodablah]

Tempted to make a version of this myself because it's simple. Single file executable, with statically linked Tor, that starts a v3 onion service (with or without client auth), hosts web server with file at URL, gives onion address URL (and client auth if any, could include the as part of URL or URL fragment or whatever depending upon approach desired). Client can use exe or Tor Browser to download it. Could add any features you want such as killing the server after first download, deadlines, etc.

Pro: doesn't upload to server and preserves anonymity. Con: slower than non-anonymous.

Here's a simple code example of a v2 onion file server using external Tor process w/ no auth: https://github.com/cretz/bine#example. This is essentially what onionshare does: https://github.com/micahflee/onionshare.