Okay but what is it? Like FF?
However, it acts in coordination with a system of DNS servers all over the world which misidentify your IP address, making it impossible to know who/where you are.
The problem is, the "onion routing" scheme is hackable by man-in-the-middle impersonations. If as few as about a half dozen of the volunteers providing service are compromised (and they probably have been) your location and history will be known to the man-in-the-middle, so it's likely that the TOR network is thoroughly infiltrated by state actors. No one knows for sure.
Its origins are also murky; it's possible (likely?) that the routing system was created by US national intelligence; the concept behind it certainly was.