What is the name for "section topics" printed in the margins
Although many marginal notes are made by hand, the term marginalia is also often used for printed ones. There is even a book about &quot;printed marginalia&quot;. A definition of marginalia given here states

The term &quot;marginalia&quot; generally refers to handwritten or printed text situated at the borders of the page.

Depending on the textual content, words like gloss, annotation or side note can also apply (although the latter also has a more metaphorical meaning).