Introduction to layout XML files

XML files have had a main role in AC since Magento 1. Files related to the layout system, known as layout XML files, determine the structure of each rendered page, arrangement of blocks, containers, and even UiComponents (in AC; this was not present in Magento 1).

You must understand that the Magento 2 framework is modular and highly flexible, and layout XML files are responsible for how the final page HTML output is composed. To make things even more interesting, in AC, each module can have its own layout files, which can modify the shape of any page in the entire framework.

There are hundreds of layout files in AC, so let’s start with a basic explanation of the main file types of the layout XML system. We’ll look at this from a storefront perspective. I will share all the details on this in the Layout and pages section of this chapter.

For now, let’s see what types of files are used to determine a page structure:

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