In The Last Jedi:
The Resistance fleet is tracked through hyperspace by the First Order after they make their jump away from their old base.
As soon as the FO ships appear, the Resistance immediately come to the (correct) conclusion as to the tech that was used.
Why would they assume the use of this tech, that they have never encountered before, as opposed to the more common technique of
tracking a ship through the use of a homing beacon.