Magento - determine which xml layout file the page is using?

Question

I tried reading the documentation, but I still don't understand how the magento xml layout files work.

In the directory app/design/frontend/default/modern/layoutI see a lot of xml files. How to determine which xml file any page on a website uses?

For example, if I was on the main page in http://mysite.com, what format of the xml file do I use? What if Im on http://mysite.com/hello-world, in which xml file then?

Answer 1

High level version: you never use just one layout file.

All XML files are combined into a gigantic XML file called package composition.

Each page then requests a series of special string characters called “descriptors”.

, .

XML , .

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(, , )

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Answer 2

"" (, , ), //, , , <catalog_product_view>. , , . , , , .