瑜伽論記 1.616

1.616

滓穢處，非滓穢處者，諸天等所食無穢，人等所食則有變穢，及一切遍諸根所隨逐者，則前二種身根遍在四根中，義以為第三。

Regarding "places with residue and places without residue": the food consumed by the gods and the like has no foul residue, whereas the food consumed by humans and the like transforms into foul residue. And "that which is universally followed by all faculties" means that the body faculty of the two preceding kinds is pervasive throughout the four faculties, which conceptually serves as the third.