Tu puer propheta altissimi vocaberis preibis

The space for the rubric for this Mass was left empty on the manuscript; it could be Joannis Baptistae,8 (In week after John the Baptist) or Octava Joannis Bapt. (July 1st).

In most other sources the Communion Tu puer is 2nd mode. In this source however it is in the indistinct mode of Dsolre: thus it could be 1st or 2nd mode (without the communion verse differentia it may be impossible to tell).