In Amharic, the main biblical commentary is known as the Andemta commentary. This is divided into four sections, which cover the Old Testament, the New Testament, Patristic works, and Monastic canons and texts.
The Andemta commentary is an explanation in Amharic of passages in the Ethiopian biblical, patristic and liturgical books, themselves written in Geez. The commentary does discuss textual variants and emendations, showing that the authors are aware of scribal issues. The Geez OT is based on the Septuagint, rather than the Hebrew text.
The commentary is little known in the West. Manuscripts are uncommon. The late Roger Cowley (d. 1988) worked in Ethiopia for 15 years, and managed to amass copies of the entire collection, which he bequeathed to the British Library. He encountered great difficulty even in identifying manuscripts. However the Andemta commentary has now at least been printed for a number of books of the bible; Psalms, the 5 books of Solomon, Ecclesiasticus, Ezekiel, the 4 gospels, Acts, the letters of Paul, the Catholic letters, and Revelation.
Cowley does refer to the commentary on Philoxenus (of Mabbug) in the Andemta commentary in his own book on Ethiopian Biblical Interpretation, but otherwise I have been unable to find anything on the subject of the patristic commentaries.
-  British Library Endangered Archives project 336, here. “This project aims to digitise the andemta (Ge’ez – Amharic commentary) manuscripts of biblical and patristic commentaries made according to the lay bet exegetical tradition. The formerly famous exegetical school of thought known as lay bet has survived only in the much endangered codices which are kept mostly in private and in rare monastic collections in Eastern Gojjam and Southern Gondar regions, Ethiopia. The material includes 70-75 codices which cover the Ge’ez – Amharic commentary of the four sections of Ethiopian Exegesis: Old Testament, New Testament, Patristic Works and Monastic Canons & Writings.” ↩
-  K. Stoffregen-Pedersen, Traditional Ethiopian exegesis of the book of Psalms, 1995, p.5 ↩
-  K. Stoffregen-Pedersen, Traditional Ethiopian exegesis of the book of Psalms, 1995, p.2 ↩
-  K. Stoffregen-Pedersen, p.3. ↩