Add deprecation for the site-tagline block

packages/block-library/src/site-tagline/deprecated.js

@@ -0,0 +1,66 @@
+/**
+ * Internal dependencies
+ */
+import cleanEmptyObject from '../utils/clean-empty-object';
+
+/**
+ * Migrates the current style.typography.fontFamily attribute,
+ * whose value was "var:preset|font-family|helvetica-arial",
+ * to the style.fontFamily attribute, whose value will be "helvetica-arial".
+ *
+ * @param {Object} attributes The current attributes
+ * @return {Object} The updated attributes.
+ */
+const oldFontFamilyMigration = ( attributes ) => {
+	if ( ! attributes?.style?.typography?.fontFamily ) {
+		return attributes;
+	}
+
+	const fontFamily = attributes.style.typography.fontFamily
+		.split( '|' )
+		.pop();
+	delete attributes.style.typography.fontFamily;
+	attributes.style = cleanEmptyObject( attributes.style );
+
+	return {
+		...attributes,
+		fontFamily,
+	};
+};
+
+const deprecated = [
+	{
+		attributes: {
+			textAlign: {
+				type: 'string',
+			},
+		},
+		supports: {
+			html: false,
+			color: {
+				gradients: true,
+			},
+			spacing: {
+				margin: true,
+				padding: true,
+			},
+			typography: {
+				fontSize: true,
+				lineHeight: true,
+				__experimentalFontFamily: true,
+				__experimentalFontWeight: true,
+				__experimentalTextTransform: true,
+				__experimentalLetterSpacing: true,
+			},
+		},
+		save() {
+			return null;
+		},
+		migrate: oldFontFamilyMigration,
+		isEligible( { style } ) {
+			return style?.typography?.fontFamily;
+		},
+	},
+];
+
+export default deprecated;

packages/block-library/src/site-tagline/index.js

@@ -4,11 +4,13 @@
 import metadata from './block.json';
 import edit from './edit';
 import icon from './icon';
+import deprecated from './deprecated';
 
 const { name } = metadata;
 export { metadata, name };
 
 export const settings = {
 	icon,
 	edit,
+	deprecated,
 };