The squatting position, otherwise known as “Rice Paddy Prone,” isn’t as common as it once was. It is a moderate stability position that supports both elbows, making it more stable than kneeling yet keeping a high level of mobility. Its higher center of gravity will still be less stable than sitting or prone, though.
It was a traditionally taught marksmanship position but lost popularity after the Korean conflict. It’s been left out of military marksmanship manuals for a long time, though still taught in some shooting schools. The position returned in the 2016 edition of TC 3-22.9.