It is legitimate to see in it an invitation to the future ecumenical mass, practical expression of ecumenical communion.
The Pope began by praising the common commemoration of 500 years of the Protestant Reformation, allowing a glimpse of a progressive evolution on "the nature of the Church"; which says a lot about the increasingly marked break between the true Catholic Church and the new conciliar Church:

«As the Week of Prayer for Christian unity ends, let's go back in thought, full of joy, to the common commemoration of the Reformation last year"

«a fruitful opportunity for ecumenism, because it marked not a point of arrival, but a starting point in the ecumenical search for full and visible unity among us, under the triple sign of gratitude, of repentance and hope, all three indispensable if we really want to heal our memory. It is no coincidence that our efforts are oriented towards the study of a priority ecumenical question on which we intend to focus in the future, or the question of the nature of the Church."
«…we understood – explains Jorge Mario Bergoglio – the event of the Reformation as an invitation to face together the loss of credibility of Christianity, an invitation to give renewed strength to the common confession of the Triune God. The year that has just ended reminded us of the time when unity among Christians had not yet been broken. This is why Lutherans and Catholics were able to celebrate the commemoration of 2017 only one way: in ecumenical communion."

Il “Papa” At this point the Argentine makes an unprecedented revelation about the doctrinal agreement that would finally be reached with the Lutherans:

«With joy and gratitude I receive from your hands today the document recently produced by the Lutheran-Catholic Dialogue Commission of Finland, entitled “Growing Communion. Declaration on the Church, the Eucharist and the ministry". In these crucial contents we can see the decisive themes around which ecumenical dialogue can and must be carried forward. Indeed, after the consensus reached between Lutherans and Catholics on fundamental questions relating to the doctrine of justification, the ecclesiological implications of such an agreement must necessarily be part of the agenda of ecumenical dialogues."
So let's find out, in a sprint, from the mouth of Pope Francis, in a message addressed to Protestants, that consensus has been reached "between Lutherans and Catholics on fundamental questions relating to the doctrine of justification"!
Simply put, the Conciliar Church therefore ended up adopting Protestant theology on this question, so long as, let it be known, Lutherans have not changed their doctrine on justification… At this point, all that remains is to put this agreement into practice and, why not, through the official birth of the future ecumenical mass, conciliar fixation circulating in the corridors of the Apostolic Palaces…
The conciliar Church of the Bergoglian era intones the definitive ruin of the few strings of Catholic doctrine that still remain within it...
The neo-Protestant and neo-modernist Conciliar Church from year to year it moves away in an impressive way, both overall and in detail, by the Catholic Church…