Hi @rak and welcome, you would not have access to the source code of Website Builder. Most customers with little or mostly general technical knowledge opt for simplicity and ease of use and that is who the Website Builder is designed for. While it is a robust and build-able solution for the majority of customers you would not be able to get down to the level you desire for your needs.
You are, of course, welcome to use your own HTML coding solutions on our hosting.
Thomas D. - GoDaddy | Community Moderator 24/7 support available at x.co/247support