Good questions @manjula - We do carefully avoid GPL code in software that we distribute for reasons discussed here.
Since this pedicle screw simulation code isn’t a Slicer Extension the issue hadn’t come up yet and this repository didn’t explicitly state. It’s okay for people to write Slicer code and offer
it under any license they choose, but we can’t redistribute it under the terms of GPL without triggering the copyleft for everyone.
Since this repository is not under our control we really can’t assume anything about the license terms and are best off getting an explicit statement from the authors.