Greetings all, Hari Om.
I'm not able to find any files under the Notes and Homework folders for week 20 on google drive. Can someone please share them?
There are a couple of सूत्रs described in the धातुपाठ page you mention. I don't understand the explanation well, but here's what seems to be happening. First, the त् प्रत्यय gets लोप. Following that, the letters beyond the final खर् (ख् to स्) to the end of the word are replaced by विसर्ग. I don't think these sutras have been discussed in the lessons so far.
It will be best for Varun-ji to explain this to us.