Given the specificity of the query, here are the most likely sources (note: always respect copyright laws; much liturgical music is free for non-commercial parish use but may be under copyright if published after 1970).
Brother Leo left us the Scripta Leonis (Writings of Leo), where he recorded the "Blessing of Brother Leo" alongside the famous Laudes Dei Altissimi (Praise of God Most High). The number 13 may also resonate with Franciscan tradition: benedizione a frate leone spartito pdf 13
Thus, the "13" in the keyword might be a liturgical reference, not merely a page number. Given the specificity of the query, here are
Once you locate your benedizione a frate leone spartito pdf 13, here’s how to best utilize it: Thus, the "13" in the keyword might be
Let us imagine a typical “Versione 13” of this blessing. Based on common practices in Italian sacred music, such a score would be:
The number 13 might appear in the header: “N. 13 - Raccolta dei Canti Francescani” or “Edizione 13/2020”.