Speed limit-free highways in Germany?

Thanks.

“For those vehicles where the 100 km/h limit applies there is no limit on “Autobahnen” (motor ways) and highways outside city limits that are dual carriage ways with a physical separation or have at least two lanes per direction. All these limits as well as the “no limit” can be overridden by signage.”

I guess it means that if I drive a car, I can drive as fast as I want, provided there’s not explicit speed limit.

How would I use OverpassTurbo to find how many kms of such highways are available in Germany to drive a car with no speed limit?