The Custom Content section serves as a blank slate, that allows you to easily include image content and custom code into a page or even the homepage of your shop. This section is a great way to integrate code snippets from 3rd party apps or even extend the theme's existing design with your own unique content.
It comes with two blocks: Image and HTML
This gives you the option to insert an image and adjust the block width on the page. Multiple blocks can be added and unlike other image-based sections, this section will not responsively adjust the image based on a focal point. It will render as a fixed-width image based on the width and alignment settings you choose.
This can be really useful for app integrations or easily including your own custom code into your theme.