Links inside the same content-file

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In general…

Pure markdown

In your site configuration, enable markdown attributes for block level elements (blockquotes, fenced code blocks, headings, horizontal rules, lists, paragraphs, and tables).

[markup.goldmark.parser.attribute]
title = true # default is true
block = true # default is false

Then in your markdown you can do:

This is a [link](#reference) to a block level element on the page.

This is the reference.
{#reference}

Markdown mixed with HTML

In your site configuration, allow HTML in content:

[markup.goldmark.renderer]
unsafe = true # default is false

This is safe if you control the content.

Then in your markdown you can do:

This is a [link](#reference) to a block level element on the page.

<div id="reference">
This is the reference.
</div>