<type name="Amazon\Payment\Gateway\Request\CaptureRequestBuilder">
    <arguments>
        <argument name="config" xsi:type="object">
            AmazonGatewayConfig
        </argument>
        <argument name="coreHelper" xsi:type="object">
            Amazon\Core\Helper\Data
        </argument>
        <argument name="productMetadata" xsi:type="object">
            Magento\Framework\App\ProductMetadata
        </argument>
    </arguments>
</type>

This is a type configuration.

This configuration is for the base area. Base area configurations will apply to all the sub-applications.

This configuration tells the Object Manager that when a user wants a Amazon\Payment\Gateway\Request\CaptureRequestBuilder object that the following arguments should be used in the foo object's constructor.

• $config = new AmazonGatewayConfig (...)
• $coreHelper = new Amazon\Core\Helper\Data (...)
• $productMetadata = new Magento\Framework\App\ProductMetadata (...)

<preference for="Magento\Framework\App\ProductMetadataInterface"
            type="Magento\Framework\App\ProductMetadata"></preference>

This is a preference configuration.

This configuration is the application level configuration (`app/etc/di.xml`) fo the object manager. It is not a part of a specific module, but will apply to all sub-applications in Magento 2 (cart, admin, api, cron, etc).

This preference configuration tells the Object Manager when a user wants a Magento\Framework\App\ProductMetadataInterface object that it should return a Magento\Framework\App\ProductMetadata object.