The code is dynamically generated by the database. If you want to add some things to make your site SEO friendly, learn how to use header tags and images as well as meta descriptions for your pages. If you are talking about making it load faster, here is a LINK.
Basically there are built in seo plug in available in the Joomla template, please try to install these plugins in the backend of the website in this way you will be able to optimize your Joomla based website.