In his commentary on the second verse of the Devīmāhātmya, Śantanu gives a string of glosses of the word māyā. The first gloss he gives is: māty asyāṃ viśvaṃ māyā/ mākābhyām ayac/  The first part of this is quite straightforward, but I can't make heads or tails of the second part. It has the appearance of a sūtra providing for an affix ayaC after mā and kā (kai?), but it's not from the Aṣṭādhyāyī, Mahābhāṣya, or the Uṇādisūtras. And Uṇādisūtra 4.109 (māchāsasisūbhyo yaḥ) is normally cited to derive māyā. If anyone has any insight on what this might be, please let me know.

If you want to see the larger context, this is a link for a PDF of a beautiful 1903 edition by Gaṅgāviṣṇu Śrīkṛṣṇadāsa that our library at Brown digitized, in which this comment appears on 2r: (The file is 169 MB)
https://www.dropbox.com/s/wksu2wnlb5v0gat/Durg%C4%81%C5%9Bapta%C5%9Bat%C4%AB%20%C5%9A%C4%81ntanav%C4%AB%20comm.pdf?dl=0
 

Thanks,

David