Where is the transmission function stored?
The transmission function is printed in the output file as a function of the spin, the k-point and the energy, and the same information is also stored in the file .TRANS.
The file .AVTRANS contains the k-averaged transmission, meaning that for a given spin and energy value, the contribution from each k-point is summed with it’s respective weight. This is the function that is ultimately integrated to get the electronic current.