Brief mention is made in Lesson 8 of the Nyingma definitions of self-voidness and other-voidness.

There is a considerable amount of information on this topic on the Berzin Archives Study Buddhism website, in particular this five part series entitled "Main Points of Self-Voidness and Other-Voidness".

Lesson four states, in part,
"self-voidness is a voidness or a total absence of impossible ways of existing"
"When we speak about other-voidness, we are speaking about clear light mind or rigpa."
"Rigpa is referring to the clear light mind when it has this manifest understanding of voidness. So there’s a difference: rigpa itself is not stained by these habits of grasping for impossible existence and so on, because it has that full understanding of voidness. So there’s a difference between clear light mind and rigpa; rigpa is a subcategory of clear light mind."

Also note that each of the five lessons in the series have both transcripts and audio files available so you can read/listen online or download and save for offline use.