瑜伽論記 17.301

17.301

言又諸解脫，由所知障解脫所顯等者，此是變易不變易異熟生受，即是白清無記法，障所知故是所知障類。又通染受但障所知，故得所知障名，二乘斷此名斷所知障。

Regarding the statement 'Furthermore, the liberations are revealed by liberation from the knowable obstruction, and so forth': This refers to mutable and immutable feeling born of maturation, which is white, pure, and indeterminate phenomena. Because it obstructs the knowable, it belongs to the category of the knowable obstruction. Furthermore, it also applies to defiled feeling that merely obstructs the knowable, and so receives the name of knowable obstruction; when the two vehicles sever this, it is called severing the knowable obstruction.