In the South Asian Canonical Text list, the Tamil work of Ettuttigai was included.
It turns out that the pre-bhakti Tamil texts were "dramatically re-discovered in late 19th century", per A.K.Ramanujan in his Poems of Love and War: From the Eight Anthologies and Ten Long Poems of Classical Tamil, p.xi-xiv.
Per my own criteria - "rediscovered texts" would not be counted as canonical texts.
Thus the need to replace this with another worthy text! If I went back to the history of the list, I should be choosing Tukaram. However, to avoid over-representing (late) Bhakti poets, or authors from Maharashtra (vs. Bengal), I am included to replace Ettuttigai with Bhartrhari's Satakatraya, thereby replacing a South Indian's Tamil language work with a North Indian's Sanskrit work.