俱舍論頌疏論本 1.201

1.201

釋曰：空界謂竅隙者，正明空界非虛空也。唯取門窓及口鼻等內外竅隙，名為空界。

Commentary: 'The space element refers to apertures' directly clarifies that the space element is not unconditioned space (ākāśa). Taking only inner and outer apertures such as doors, windows, mouths, and noses, it is called the space element.