hugo/docs/content/en/readfiles/sectionvars.md

.CurrentSection

The page's current section. The value can be the page itself if it is a section or the homepage.

.FirstSection

The page's first section below root, e.g. /docs, /blog etc.

.InSection $anotherPage

Whether the given page is in the current section.

.IsAncestor $anotherPage

Whether the current page is an ancestor of the given page.

.IsDescendant $anotherPage

Whether the current page is a descendant of the given page.

.Parent

A section's parent section or a page's section.

.Section

The section this content belongs to. Note: For nested sections, this is the first path element in the directory, for example, /blog/funny/mypost/ => blog.

.Sections

The sections below this content.