<type name="Magento\Ui\Config\Converter">
    <arguments>
        <argument name="reader" xsi:type="object">
            Magento\Ui\Config\Reader\DefinitionMap
        </argument>
        <argument name="parser" xsi:type="object">
            Magento\Ui\Config\Argument\Parser\Composite
        </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 Magento\Ui\Config\Converter object that the following arguments should be used in the foo object's constructor.

• $reader = new Magento\Ui\Config\Reader\DefinitionMap (...)
• $parser = new Magento\Ui\Config\Argument\Parser\Composite (...)

<type name="Magento\Ui\Config\Argument\Parser\Composite">
    <arguments>
        <argument name="parsers" xsi:type="array">
            <item name="array" xsi:type="object">
                Magento\Ui\Config\Argument\Parser\ArrayType
            </item>
            <item name="configurableObject" xsi:type="object">
                Magento\Ui\Config\Argument\Parser\ConfigurableObjectType
            </item>
            <item name="xpath" xsi:type="object">
                Magento\Ui\Config\Argument\Parser\XpathType
            </item>
            <item name="converter" xsi:type="object">
                Magento\Ui\Config\Argument\Parser\ConverterType
            </item>
        </argument>
        <argument name="discriminator" xsi:type="string">
            xsi:type
        </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 Magento\Ui\Config\Argument\Parser\Composite object that the following arguments should be used in the foo object's constructor.

• $parsers = [...items...];
• $discriminator = "xsi:type";

<preference for="Magento\Ui\Config\Argument\ParserInterface"
            type="Magento\Ui\Config\Argument\Parser\Composite"></preference>

This is a preference configuration.

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

This preference configuration tells the Object Manager when a user wants a Magento\Ui\Config\Argument\ParserInterface object that it should return a Magento\Ui\Config\Argument\Parser\Composite object.