This short tutorial describes how to set Notepad++ as default editor for .xml files. Simply register the extension in the app's preferences.

Here, check the Enabled option. Under the Options window, specify the path to the .xml file that contains the Start layout. For example, C:\Users\Test01\StartScreenMarketing.xml.

This seems like the canonical XQuery use case. What you have to do is find an XQuery library you like (I'm a fan of Saxon) and run a for-each XQuery (example here) that will get you your elements.

In the middle part of this decade, Microsoft engaged in an extensive effort to create open standards derived from its own XML-based file formats, such as XPS and Office XML.