How can I download a streaming file without the file's specific address?
What do you suppose happens in the back-end when you request a download of a file from a given location? The file gets converted to some encoding (in the most basic/general case: binary) and streamed over a network connection to you as a receiver.

Really for all practical purposes you wouldn't be able to distinguish downloading a 'real' file from download/receiving an active (bit)stream of that file as they're generally the same thing: bits being pushed across a connection.