The XML Page View is used when the page type of a Window is XML. The view is similar to the HTML Page View, but lacks the Browser View. It is split into several sub views, as shown below: the Address Bar, the Tag Path View and the XML View.
The XML Page View may show XML document loaded in two different ways: from an URL (e.g. as the result of executing a Load Page Step Action or as the response from a web service call) or from an XML variable. If the document is loaded from an URL it is read-only and can therefore not be modified. If the document is loaded from a variable it is essentially a view on that variable and any modification of the document is reflected in the value of the variable.
The Address Bar show the URL of the document in the Page View. You can also (like in a browser) enter a new URL in this and if you press Enter a new Load Page step will be inserted in the robot before the current step. The Address Bar is only present for document loaded from an URL and not from a variable.
In the Tag Path View, you see the path from the root tag of the page to the selected tag. In the XML View you see the XML of the page.
In almost all other aspects the XML Page View works like the HTML Page View, you can left-click to select, you right-click to to configure and insert new steps and the functionality of the toolbar buttons is the same. The options available in the right-click menu is selected such that these are relevant for XML and if an option is shown, but is not enabled it means that it cannot be used with the given selection, e.g. Extract Attribute is only enabled if the selected XML tag has at least one attribute.