first two lines on examples

Hi,

I have a question on the example you provided. On each file of "dat_1.xx", the first line consists of two columns, where the  value in the first column is 2500.0000000000 and the second is within the margin of the reaction coordinate. I would like to know what those two values are, where/how to obtain them. and how do they impact the overall PMF.

Thank you