7. Later Additions
Red "bar" lines
While most bar lines on the extant leaves are characterized by extremely thin lines in black ink, thicker red lines are found sporadically across some of the chants on many of the leaves. These lines were almost certainly added later and are likely an indication of the manuscript's active use by its community. While their exact function is unknown it seems they are included in chants with more complex melodies or to assist in visualizing more clearly where to switch syllables in certain words.
Flats and Sharps
Different styles of notations indicating flat and sharp notes are also included in several of the leaves. Given their differing appearances, it seems likely that some of these were written by the original scribe, whereas others were added later
Added Chant
The extant leaf at Harvard University's Houghton library includes an entire chant added at the bottom margin of the leaf clearly written in a later hand and by a non-professional scribe.