The following passage is from Yāmuna’s Ātmasiddhi and it is a description of the Advaita position about the brahman as being tantamount to consciousness:
ato ‘syā na meyaḥ kaścid api dharmo ‘sti. ato nirdhūtanikhilabhedavikalpanirdharmaprakāśamātraikarasā kūṭasthanityā saṃvid evātmā paramātmā ca. yathāha yānubhūtir ajāmeyānantātmā iti. saiva ca vedāntavākyatātparyabhūmir iti (ĀS, pp. 29–30 of the 1942 edition)
Therefore this (consciousness) has no characteristic as its knowable content. Therefore, this very consciousness is eternal, uniform and it consists of light-only, without characteristics, in which all conceptualisations of difference have been dissolved. This consciousness alone is the self (ultimately identical with the single brahman, but illusory identified as one’s own self) and the supreme self (i.e., the brahman). As it has been said: ”That experience (i.e., consciousness) is unborn, cannot become a knowledge content, it is endless, it is the self”*. And this alone is the ultimate meaning (tātparya) of the Upaniṣads’ sentences.
The quote within the passage (yānubhūtir ajāmeyānantātmā) could be an Upaniṣadic quote, but I could not locate it. Do readers know it? And, more importantly: Yāmuna’s description seems fair to me. Do readers more expert in Advaita agree?