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Qubes is an open-source operating system designed to provide strong security for desktop computing.
TorBirdy is Torbutton for Thunderbird, Icedove and related Mozilla mail clients.
Polipo is a web proxy which supports forwarding and caching. It was up to 2010 part of the Tor Browser Bundle.
TorVM is a feature for the Qubes operating system that allows for virtual machines to be transparently proxied through Tor.