New feature: Added "Newsletter Subscription Form" widget

app/code/core/Mage/Newsletter/Block/Widget/Subscribe.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * OpenMage
+ *
+ * This source file is subject to the Open Software License (OSL 3.0)
+ * that is bundled with this package in the file LICENSE.txt.
+ * It is also available at https://opensource.org/license/osl-3-0-php
+ *
+ * @category   Mage
+ * @package    Mage_Newsletter
+ * @copyright  Copyright (c) 2006-2020 Magento, Inc. (https://www.magento.com)
+ * @copyright  Copyright (c) 2024 The OpenMage Contributors (https://www.openmage.org)
+ * @license    https://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
+ */
+
+/**
+ * Newsletter subscribe form Widget
+ *
+ * @category   Mage
+ * @package    Mage_Newsletter
+ * @method string getSuccessMessage()
+ * @method string getErrorMessage()
+ * @method string getFormActionUrl()
+ */
+class Mage_Newsletter_Block_Widget_Subscribe extends Mage_Newsletter_Block_Subscribe implements Mage_Widget_Block_Interface
+{
+    protected function _construct()
+    {
+        parent::_construct();
+    }
+}

app/code/core/Mage/Newsletter/etc/widget.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0"?>
+<!--
+/**
+ * OpenMage
+ *
+ * This source file is subject to the Academic Free License (AFL 3.0)
+ * that is bundled with this package in the file LICENSE_AFL.txt.
+ * It is also available at https://opensource.org/license/afl-3-0-php
+ *
+ * @category   Mage
+ * @package    Mage_Newsletter
+ * @copyright  Copyright (c) 2006-2020 Magento, Inc. (https://www.magento.com)
+ * @copyright  Copyright (c) 2024 The OpenMage Contributors (https://www.openmage.org)
+ * @license    https://opensource.org/licenses/afl-3.0.php Academic Free License (AFL 3.0)
+ */
+-->
+<widgets>
+    <newsletter_subscribe type="newsletter/widget_subscribe" translate="name description" module="newsletter">
+        <name>Newsletter Subscribe Form</name>
+        <description>Newsletter Subscribe Form</description>
+        <is_email_compatible>0</is_email_compatible>
+        <parameters>
+            <template translate="label">
+                <label>Template</label>
+                <visible>1</visible>
+                <type>select</type>
+                <value>newsletter/subscribe.phtml</value>
+                <values>
+                    <default translate="label">
+                        <value>newsletter/subscribe.phtml</value>
+                        <label>Newsletter Form Default Template</label>
+                    </default>
+                </values>
+                <sort_order>10</sort_order>
+            </template>
+        </parameters>
+    </newsletter_subscribe>
+</widgets>

app/locale/en_US/Mage_Newsletter.csv

@@ -140,3 +140,4 @@
 "You have been unsubscribed.","You have been unsubscribed."
 "Your subscription has been confirmed.","Your subscription has been confirmed."
 "This email address is already confirmed.","This email address is already confirmed."
+"Newsletter Subscribe Form","Newsletter Subscribe Form"