For the design of this website (as of 2022-10-11), I wanted to include the number of pages in a section—e.g., in the menu. I found a post on the Zola forum¹ where I learnt about the get_section and a section's pages variable. Then in the Tera documentation², I found the length function.

Between the 2 of these, I'm able to display the pages count.

Example

{% set notes = get_section(path="notes/_index.md") -%}
{{ notes.pages | length }}

Update: Notes have been renamed to blog (and posts).