Redirect based on a query string

I am working on project where the previous web developer has left the company. There is redirect happening based on the query string and I can’t figure out where. The example URL is https://www.example.com/?something. I want this URL to point to front-page.php, where as it is always pointing to home.php. That happens only when I have the query string something in the url. If I use somethingelse or nothing in the query string it would work fine and redirect to front-page.php.

I have read this article (https://developer.wordpress.org/themes/basics/template-hierarchy/) from WordPress but I sill can’t figure out where the redirection is happening. I want the URL to point front-page.php