Soulseek protocol used both by soulseekqt (propriatary) and nicotine-plus (open-source), so I think that it should not be in "File transfer protocols used by only one application" category. --Maciej Błędkowski (talk) 16:09, 30 September 2021 (UTC)
Aspera (end-to-end) protocol is an instance of P2P protocol? --Krauss (talk) 18:25, 13 November 2016 (UTC)