Possible Clues:

• Explanatory text
• Further comment at the bottom of the page
• School, extremely fine, raised comment
• Pay for part of score that's relatively unimportant
• It's not very important to pay bill (as Americans would have it)
• Further comment, often too complicated
• Additional information that an organist might provide
• Reference added eg to an academic text
• Fact addition
• Explanation below the text