Should I use an .njk or .html extension for pages?

[TechAurelian]

I have this setting in the .eleventy.js config file

htmlTemplateEngine: "njk",

so I can use both page-product1.njk and page-product1.html

The content of the page(s) is usually a combination of Nunjucks (including imported macros), and HTML markup.

---
title: ...
---

{% from "templates/feature-item.njk" import featureItem with context %}

<ul class="space-y-12">
  {{ featureItem(
    title  = " ...", 
    text   = " ... ",
    image  = " ... ") }}

    ...
</ul>

Should I use an .njk or .html extension for pages?

page-product1.njk or page-product1.html?

Is there a best practice?