What is the meaning of *.AVTRANS_Left-Left and Left-Right, and how to calculate the current based on them?

In TBTrans 4.1.5, the Transiesta caluclation results are outputed as many file types such as AVADOS_Left/Right, AVBDOS_Left/Right, AVBTRANS_Left/Right, AVCORR_Left/Right, AVTRANS_LL/LR/RR/RL…
I wonder which one is used to be integrated to calculate the current? And how the current is calculated? by what formula?

I have searched related Q&A in SIMUNE, e.g., Transmission function
It taught me that the file *.AVTRANS should be responsible for the current calculation. But no file alike in the output files of TBTrans 4.1.5.
I have also tried to integrate the *.AVTRANS_Left-Left and Left-Right to re-calculate the current, but the result does not coincide with the *.out of TBTrans.

I am really confused and will be so grateful if the developer could make it clear.