Context: How does \Magento\Framework\Api\ExtensionAttribute\JoinProcessor::process() work?
\Magento\Framework\Api\ExtensionAttribute\JoinProcessor::process()
Details: How does \Magento\Framework\Api\ExtensionAttributesFactory::getExtensibleInterfaceName() work?
\Magento\Framework\Api\ExtensionAttributesFactory::getExtensibleInterfaceName()
See also:
join-processor
extension-attributes