The Tor Browser is a cross-platform portable Tor client integrated with a browser (based on Firefox Extended Support Release). It is 100% FLOSS software and includes privacy-related extensions like Privacy Badger and NoScript out-of-box.
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Pro Tor sets the standard for safe and private browsing
If you follow their instructions religiously, Tor is the nec plus ultra in terms of safety and privacy. For the time being at least.
Can be installed and run on a portable device such as a USB stick.