di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Catalog\Model\Product\LinkTypeProvider">
        <arguments>
            <argument name="linkTypes" xsi:type="array">
                <item name="customlink" xsi:type="const">Magelearn\LinkProduct\Model\Product\Link::LINK_TYPE_CUSTOMLINK</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Catalog\Model\ProductLink\CollectionProvider">
        <arguments>
            <argument name="providers" xsi:type="array">
                <item name="customlink" xsi:type="object">Magelearn\LinkProduct\Model\ProductLink\CollectionProvider\CustomLinkProducts</item>
            </argument>
        </arguments>
    </type>
    <!-- used for import custom link products via import CSV feature -->
    <type name="Magento\CatalogImportExport\Model\Import\Product\LinkProcessor">
        <arguments>
            <argument name="linkNameToId" xsi:type="array">
                <item name="_customlink_" xsi:type="const">Magelearn\LinkProduct\Model\Product\Link::LINK_TYPE_CUSTOMLINK</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\CatalogImportExport\Model\Import\Product\Type\AbstractType">
        <plugin sortOrder="1" name="magelearnLinkProductAbstractType" type="Magelearn\LinkProduct\Plugin\Model\Import\Product\Type\AbstractTypePlugin"/>
    </type>
</config>