typst/docs/reference/library/introspection.md

Interactions between document parts.

This category is home to Typst's introspection capabilities: With the counter function, you can access and manipulate page, section, figure, and equation counters or create custom ones. Meanwhile, the query function lets you search for elements in the document to construct things like a list of figures or headers which show the current chapter title.

Most of the functions are contextual. It is recommended to read the chapter on [context] before continuing here.