So this question might be rather meaningless in a few months, but I figured I might as well ask here in case someone can parse the Pope's meaning
The Holy Father said:
I am also providing two prayers to Our Lady that you can recite at the end of the Rosary, and that I myself will pray in the month of May, in spiritual union with all of you. I include them with this letter so that they are available to everyone. - Letter on the Month of May - Full text, including prayers
I know lots of times there are prayers that go at the end of some offices where they're "pray this today and that the other day" and they don't give much more guidance. It just doesn't make much sense to me to add two prayers to the end of a 20 minute mediation, why not just call it one long prayer?
Anyway, I'm guessing nobody knows the answer to this without asking the Pope, but if there's any similarity to other special prayers, that might answer the question too.