Can someone explain a bit more how it works? I don't understand the "We then train linear probes on the last token activations to predict the real latitude and

Can someone explain a bit more how it works? I don't understand the "We then train linear probes on the last token activations to predict the real latitude and longitudes of each place." I've looked up linear probing on Wikipedia, but it's not obvious how it can be used to predict lat and long.