Add a Dropdown block for use in Navigation

lib/blocks.php

@@ -22,6 +22,7 @@ function gutenberg_reregister_core_block_types() {
 				'column',
 				'columns',
 				'cover',
+				'dropdown',
 				'gallery',
 				'group',
 				'heading',
@@ -53,6 +54,7 @@ function gutenberg_reregister_core_block_types() {
 				'block.php'                     => 'core/block',
 				'calendar.php'                  => 'core/calendar',
 				'categories.php'                => 'core/categories',
+				'dropdown.php'                  => 'core/dropdown',
 				'file.php'                      => 'core/file',
 				'latest-comments.php'           => 'core/latest-comments',
 				'latest-posts.php'              => 'core/latest-posts',

packages/block-library/src/dropdown/block.json

@@ -0,0 +1,64 @@
+{
+	"apiVersion": 2,
+	"name": "core/dropdown",
+	"title": "Dropdown",
+	"category": "design",
+	"parent": [
+		"core/navigation"
+	],
+	"description": "Add a submenu dropdown to your navigation.",
+	"textdomain": "default",
+	"attributes": {
+		"label": {
+			"type": "string"
+		},
+		"type": {
+			"type": "string"
+		},
+		"description": {
+			"type": "string"
+		},
+		"rel": {
+			"type": "string"
+		},
+		"id": {
+			"type": "number"
+		},
+		"opensInNewTab": {
+			"type": "boolean",
+			"default": false
+		},
+		"url": {
+			"type": "string"
+		},
+		"title": {
+			"type": "string"
+		},
+		"kind": {
+			"type": "string"
+		},
+		"isTopLevelItem": {
+			"type": "boolean"
+		}
+	},
+	"usesContext": [
+		"textColor",
+		"customTextColor",
+		"backgroundColor",
+		"customBackgroundColor",
+		"overlayTextColor",
+		"customOverlayTextColor",
+		"overlayBackgroundColor",
+		"customOverlayBackgroundColor",
+		"fontSize",
+		"customFontSize",
+		"showSubmenuIcon",
+		"style"
+	],
+	"supports": {
+		"reusable": false,
+		"html": false
+	},
+	"editorStyle": "wp-block-dropdown-editor",
+	"style": "wp-block-dropdown"
+}