Q:

Overriding Phtml File in magento 2?

I am overriding this file

vendor\magento\module-backend\view\adminhtml\templates\widget\grid\extended.phtml

I am overriding it in 

app\code\Vendor\Module\view\adminhtml\templates\widget\grid\extended.phtml

Since it a template file i also need to create backend_widget_grid.xml at

app/code/{Vendor}/{Module}/view/frontend/layout/

with the following content
<?xml version="1.0"?>
<page layout="1column" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <body>
        <referenceBlock name="widget.extended">
            <action method="setTemplate">
                <argument name="template" xsi:type="string">{Vendor}_{Module}::widget/grid/extended.phtml</argument>
            </action>
        </referenceBlock>
    </body>
</page>

But I am not sure if the referenceBlock or if the backend_widget_grid.xml name I am entering is incorrect since my edit doesn't show?

A:

You want to override a admin template but, you put it in frontend !
Try this: 

app/code/{Vendor}/{Module}/view/adminhtml/layout/

instead of : 

app/code/{Vendor}/{Module}/view/frontend/layout/

