How does `content_for_layout` load content in shopify?

@deron 

In Shopify, content_for_layout is a liquid variable that is used to load the content that is defined in a specific section, such as the main-content section in the theme file.

When a section is included in a template file using the {% section %} tag, any content that is assigned to the content_for_layout variable within that section will be rendered in the corresponding section of the template file. This allows for dynamic insertion of content into different parts of the layout, such as the header, footer, or main content area.

For example, in a section file, you may define the content like this:

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{% assign content_for_layout = "This is the main content for the section" %}

And in the corresponding template file, you may render this content in the main-content section like this:

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{{ content_for_layout }}

This will display the content "This is the main content for the section" in the main content area of the template file.