Using Index.php

index.php

Its Primary Purpose is a fallback in the WordPress Template Hierarchy if archive.php does not exist

Please reference the Template Heirarchy for use cases https://developer.wordpress.org/themes/basics/template-hierarchy/

Currently Outputs on https://wp-ecs.trainingpeaks.com/ and provides a 404 fallback when the host name is https://wp-ecs.trainingpeaks.com/