From the early Church Fathers to now.
“To whom all power in heaven and on earth has been given. For if the righteous are called the children of God, why not also the angels? Although the heavenly hosts can also sing this by rejoicing in our redemption. As the holy Pope Gregory explained, adding: "For the voice of the angels in the praise of the Creator is the very wonder of inner contemplation."”
“The present text expresses the doxology universally accorded by all creation, both heavenly and earthly, to God the Father, and to the Word who became man [ἐνανθρωπήσαντι] and was made flesh [σαρκωθέντα], that is, also glorified together with the Holy Spirit.”
The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.