Drupal FAQ: What are the Twig template file naming conventions for Drupal 8? Specifically, how do I need to name a template file so it will be used for the front page of my website?
In short, the Drupal 8 Twig “HTML” template file has this name:
and if you want to create a custom HTML front page template, use this name:
The same goes for “page” and “node” files, where the default page template file has this name:
and the name of the template for the front-page page file is this:
The same is true for “node” files.
I put this information here so I can find it easily, but there’s much more information about the Twig file-naming conventions at these drupal.org links: