Host volume: Spiritual Marian breviary: Prayers and meditations in German for the liturgical year.
Fragment: comes from a liturgical manuscript (Antiphonary?) of the 14th-15th century with "Hufnagelnotation" (german plainsong notation) and red-blue rubrics:
Download this page
St. Gallen, Stiftsbibliothek St. Gallen, Cod. Sang. 509, Front cover – Sab. Sancto 007509a and Dom. Resurrectionis 005352, 008455a and b — https://fragmentarium.ms/view/page/F-76lt