events.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">

    <!-- Attach form selector to admin -->
    <event name="addressfinder_config_source_forms_enabled">
        <observer name="admin_order_billing_address"
                  instance="AddressFinder\AddressFinder\Observer\Config\Source\Adminhtml\OrderBillingAddress"/>

        <observer name="admin_order_shipping_address"
                  instance="AddressFinder\AddressFinder\Observer\Config\Source\Adminhtml\OrderShippingAddress"/>

        <observer name="frontend_checkout_billing_address"
                  instance="AddressFinder\AddressFinder\Observer\Config\Source\Frontend\CheckoutBillingAddress"/>

        <observer name="frontend_checkout_shipping_address"
                  instance="AddressFinder\AddressFinder\Observer\Config\Source\Frontend\CheckoutShippingAddress"/>

        <observer name="frontend_customer_address_book"
                  instance="AddressFinder\AddressFinder\Observer\Config\Source\Frontend\CustomerAddressBook"/>
    </event>

    <!-- Attach admin forms -->
    <event name="addressfinder_form_config_admin">
        <observer name="admin_order_billing_address"
                  instance="AddressFinder\AddressFinder\Observer\FormConfig\Adminhtml\AddOrderBillingAddress"/>

        <observer name="admin_order_shipping_address"
                  instance="AddressFinder\AddressFinder\Observer\FormConfig\Adminhtml\AddOrderShippingAddress"/>
    </event>

    <!-- Attach regular forms -->
    <event name="addressfinder_form_config">
        <observer name="frontend_checkout_billing_address"
                  instance="AddressFinder\AddressFinder\Observer\FormConfig\Frontend\AddCheckoutBillingAddress"/>

        <observer name="frontend_checkout_shipping_address"
                  instance="AddressFinder\AddressFinder\Observer\FormConfig\Frontend\AddCheckoutShippingAddress"/>

        <observer name="frontend_customer_address_book"
                  instance="AddressFinder\AddressFinder\Observer\FormConfig\Frontend\AddCustomerAddressBook"/>
    </event>

</config>