Download it at:
https://carlosedubarreto.gumroad.com/l/mocap_mpp2sos
This version comes with a great frature for the ones that need to do the extrinsic calibration manually.
Before, you had to not only do the calibration, but also, had to locate the files to update and to process, and that was very messy.
Now you need only to select the camera to calibrate and press "Run Labelme" and the addon will deal with the confusing part.
Now the workflow can become not only easier but more straightforward.
Hope you enjoy it.