俱舍論記 1.279

1.279

「且彼經中至名識界耶」者，此下第三別明六界。將明問起。地、水、火、風如前已說，空、識未說。為即虛空無為名為空界？為一切有漏、無漏識名識界耶？

Regarding "First, in that sūtra [...] is it called the vijñāna-dhātu?": Below this is the third section, specifically explaining the six dhātus. Approaching the explanation, a question is raised. Earth, water, fire, and wind have already been discussed earlier; space and consciousness have not yet been discussed. Is unconditioned space (ākāśāsasaṃskṛta) itself called the space element (ākāśa-dhātu)? Or are all contaminated and uncontaminated consciousnesses called the vijñāna-dhātu?