Magento 2 item provider value in ui component comprise of two parts -<b>product_listing.product_listing_data_sourceFirst, product_listing (name of UI Component)Second, product_listing_data_source (Name of the data source which process data and make the UI component work with this data.)dataSource tag which contains attribute component="Magento_Ui/js/grid/provider"This component value mapped with following js file - vendor/magento/module-ui/view/base/web/js/grid/provider.jsdataSource tag also contains dataProvider with settings subtag - it contains the table primary and request field mapping which will enable ajax url for grid actions.Listingtoolbar tag : contains the filter related setting.column tag : it contains the configuration for rendering the grid columns.