diff --git a/packages/block-editor/src/components/rich-text/format-toolbar/index.js b/packages/block-editor/src/components/rich-text/format-toolbar/index.js
index 7817fc284ae52..445cd38b4cc1d 100644
--- a/packages/block-editor/src/components/rich-text/format-toolbar/index.js
+++ b/packages/block-editor/src/components/rich-text/format-toolbar/index.js
@@ -23,7 +23,7 @@ const POPOVER_PROPS = {
 const FormatToolbar = () => {
 	return (
 		<>
-			{ [ 'bold', 'italic', 'link' ].map( ( format ) => (
+			{ [ 'bold', 'italic', 'link', 'unknown' ].map( ( format ) => (
 				<Slot
 					name={ `RichText.ToolbarControls.${ format }` }
 					key={ format }
diff --git a/packages/format-library/src/default-formats.js b/packages/format-library/src/default-formats.js
index 412ae23f4b686..791cabb1f118e 100644
--- a/packages/format-library/src/default-formats.js
+++ b/packages/format-library/src/default-formats.js
@@ -12,6 +12,7 @@ import { textColor } from './text-color';
 import { subscript } from './subscript';
 import { superscript } from './superscript';
 import { keyboard } from './keyboard';
+import { unknown } from './unknown';
 
 export default [
 	bold,
@@ -25,4 +26,5 @@ export default [
 	subscript,
 	superscript,
 	keyboard,
+	unknown,
 ];
diff --git a/packages/format-library/src/unknown/index.js b/packages/format-library/src/unknown/index.js
new file mode 100644
index 0000000000000..68c6d099fcad1
--- /dev/null
+++ b/packages/format-library/src/unknown/index.js
@@ -0,0 +1,42 @@
+/**
+ * WordPress dependencies
+ */
+import { __ } from '@wordpress/i18n';
+import { removeFormat, slice } from '@wordpress/rich-text';
+import { RichTextToolbarButton } from '@wordpress/block-editor';
+import { help } from '@wordpress/icons';
+
+const name = 'core/unknown';
+const title = __( 'Clear Unknown Formatting' );
+
+export const unknown = {
+	name,
+	title,
+	tagName: '*',
+	className: null,
+	edit( { isActive, value, onChange, onFocus } ) {
+		function onClick() {
+			onChange( removeFormat( value, name ) );
+			onFocus();
+		}
+
+		const selectedValue = slice( value );
+		const hasUnknownFormats = selectedValue.formats.some( ( formats ) => {
+			return formats.some( ( format ) => format.type === name );
+		} );
+
+		if ( ! isActive && ! hasUnknownFormats ) {
+			return null;
+		}
+
+		return (
+			<RichTextToolbarButton
+				name="unknown"
+				icon={ help }
+				title={ title }
+				onClick={ onClick }
+				isActive={ true }
+			/>
+		);
+	},
+};
diff --git a/packages/rich-text/src/create.js b/packages/rich-text/src/create.js
index b9b31e1476257..7fdcf8adba762 100644
--- a/packages/rich-text/src/create.js
+++ b/packages/rich-text/src/create.js
@@ -43,7 +43,7 @@ function createEmptyValue() {
 	};
 }
 
-function toFormat( { type, attributes } ) {
+function toFormat( { tagName, attributes } ) {
 	let formatType;
 
 	if ( attributes && attributes.class ) {
@@ -65,11 +65,11 @@ function toFormat( { type, attributes } ) {
 
 	if ( ! formatType ) {
 		formatType =
-			select( richTextStore ).getFormatTypeForBareElement( type );
+			select( richTextStore ).getFormatTypeForBareElement( tagName );
 	}
 
 	if ( ! formatType ) {
-		return attributes ? { type, attributes } : { type };
+		return attributes ? { type: tagName, attributes } : { type: tagName };
 	}
 
 	if (
@@ -80,7 +80,7 @@ function toFormat( { type, attributes } ) {
 	}
 
 	if ( ! attributes ) {
-		return { type: formatType.name };
+		return { type: formatType.name, tagName };
 	}
 
 	const registeredAttributes = {};
@@ -115,6 +115,7 @@ function toFormat( { type, attributes } ) {
 
 	return {
 		type: formatType.name,
+		tagName,
 		attributes: registeredAttributes,
 		unregisteredAttributes,
 	};
@@ -368,7 +369,7 @@ function createFromElement( {
 	// Optimise for speed.
 	for ( let index = 0; index < length; index++ ) {
 		const node = element.childNodes[ index ];
-		const type = node.nodeName.toLowerCase();
+		const tagName = node.nodeName.toLowerCase();
 
 		if ( node.nodeType === node.TEXT_NODE ) {
 			let filter = removeReservedCharacters;
@@ -398,19 +399,19 @@ function createFromElement( {
 			// Ignore any placeholders.
 			( node.getAttribute( 'data-rich-text-placeholder' ) ||
 				// Ignore any line breaks that are not inserted by us.
-				( type === 'br' &&
+				( tagName === 'br' &&
 					! node.getAttribute( 'data-rich-text-line-break' ) ) )
 		) {
 			accumulateSelection( accumulator, node, range, createEmptyValue() );
 			continue;
 		}
 
-		if ( type === 'script' ) {
+		if ( tagName === 'script' ) {
 			const value = {
 				formats: [ , ],
 				replacements: [
 					{
-						type,
+						type: tagName,
 						attributes: {
 							'data-rich-text-script':
 								node.getAttribute( 'data-rich-text-script' ) ||
@@ -425,20 +426,20 @@ function createFromElement( {
 			continue;
 		}
 
-		if ( type === 'br' ) {
+		if ( tagName === 'br' ) {
 			accumulateSelection( accumulator, node, range, createEmptyValue() );
 			mergePair( accumulator, create( { text: '\n' } ) );
 			continue;
 		}
 
 		const format = toFormat( {
-			type,
+			tagName,
 			attributes: getAttributes( { element: node } ),
 		} );
 
 		if (
 			multilineWrapperTags &&
-			multilineWrapperTags.indexOf( type ) !== -1
+			multilineWrapperTags.indexOf( tagName ) !== -1
 		) {
 			const value = createFromMultilineElement( {
 				element: node,
diff --git a/packages/rich-text/src/remove-unregistered-formatting.js b/packages/rich-text/src/remove-unregistered-formatting.js
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/packages/rich-text/src/store/selectors.js b/packages/rich-text/src/store/selectors.js
index 32a50cf89020d..52aa4dead99bf 100644
--- a/packages/rich-text/src/store/selectors.js
+++ b/packages/rich-text/src/store/selectors.js
@@ -37,9 +37,15 @@ export function getFormatType( state, name ) {
  * @return {?Object} Format type.
  */
 export function getFormatTypeForBareElement( state, bareElementTagName ) {
-	return getFormatTypes( state ).find( ( { className, tagName } ) => {
-		return className === null && bareElementTagName === tagName;
-	} );
+	const formatTypes = getFormatTypes( state );
+	return (
+		formatTypes.find( ( { className, tagName } ) => {
+			return className === null && bareElementTagName === tagName;
+		} ) ||
+		formatTypes.find( ( { className, tagName } ) => {
+			return className === null && '*' === tagName;
+		} )
+	);
 }
 
 /**
diff --git a/packages/rich-text/src/test/helpers/index.js b/packages/rich-text/src/test/helpers/index.js
index 96090ea64b51a..15aa032978c66 100644
--- a/packages/rich-text/src/test/helpers/index.js
+++ b/packages/rich-text/src/test/helpers/index.js
@@ -784,6 +784,7 @@ export const specWithRegistration = [
 				[
 					{
 						type: 'my-plugin/link',
+						tagName: 'a',
 						attributes: {},
 						unregisteredAttributes: {},
 					},
@@ -808,6 +809,7 @@ export const specWithRegistration = [
 				[
 					{
 						type: 'my-plugin/link',
+						tagName: 'a',
 						attributes: {},
 						unregisteredAttributes: {
 							class: 'test',
@@ -834,6 +836,7 @@ export const specWithRegistration = [
 				[
 					{
 						type: 'core/link',
+						tagName: 'a',
 						attributes: {},
 						unregisteredAttributes: {
 							class: 'custom-format',
@@ -899,6 +902,7 @@ export const specWithRegistration = [
 				[
 					{
 						type: 'my-plugin/link',
+						tagName: 'a',
 						attributes: {},
 						unregisteredAttributes: {},
 					},
diff --git a/packages/rich-text/src/to-tree.js b/packages/rich-text/src/to-tree.js
index 8b2397013de4d..74cc08581e83c 100644
--- a/packages/rich-text/src/to-tree.js
+++ b/packages/rich-text/src/to-tree.js
@@ -35,6 +35,7 @@ function restoreOnAttributes( attributes, isEditableTree ) {
  *
  * @param {Object}  $1                        Named parameters.
  * @param {string}  $1.type                   The format type.
+ * @param {string}  $1.tagName                The tag name.
  * @param {Object}  $1.attributes             The format attributes.
  * @param {Object}  $1.unregisteredAttributes The unregistered format
  *                                            attributes.
@@ -48,6 +49,7 @@ function restoreOnAttributes( attributes, isEditableTree ) {
  */
 function fromFormat( {
 	type,
+	tagName,
 	attributes,
 	unregisteredAttributes,
 	object,
@@ -100,7 +102,7 @@ function fromFormat( {
 	}
 
 	return {
-		type: formatType.tagName,
+		type: formatType.tagName === '*' ? tagName : formatType.tagName,
 		object: formatType.object,
 		attributes: restoreOnAttributes( elementAttributes, isEditableTree ),
 	};
@@ -241,7 +243,8 @@ export function toTree( {
 					return;
 				}
 
-				const { type, attributes, unregisteredAttributes } = format;
+				const { type, tagName, attributes, unregisteredAttributes } =
+					format;
 
 				const boundaryClass =
 					isEditableTree &&
@@ -253,6 +256,7 @@ export function toTree( {
 					parent,
 					fromFormat( {
 						type,
+						tagName,
 						attributes,
 						unregisteredAttributes,
 						boundaryClass,
diff --git a/test/e2e/specs/editor/plugins/format-api.spec.js b/test/e2e/specs/editor/plugins/format-api.spec.js
index a294a2034f055..1b1d3b3d4173f 100644
--- a/test/e2e/specs/editor/plugins/format-api.spec.js
+++ b/test/e2e/specs/editor/plugins/format-api.spec.js
@@ -34,6 +34,28 @@ test.describe( 'Using Format API', () => {
 		expect( content ).toBe(
 			`<!-- wp:paragraph -->
 <p>First <a href="https://example.com" class="my-plugin-link">paragraph</a></p>
+<!-- /wp:paragraph -->`
+		);
+	} );
+
+	test( 'should show unknow formatting button', async ( {
+		editor,
+		page,
+	} ) => {
+		await editor.insertBlock( {
+			name: 'core/paragraph',
+			attributes: { content: '<big>test</big>' },
+		} );
+		expect( await editor.getEditedPostContent() ).toBe(
+			`<!-- wp:paragraph -->
+<p><big>test</big></p>
+<!-- /wp:paragraph -->`
+		);
+		await page.keyboard.press( 'ArrowRight' );
+		await editor.clickBlockToolbarButton( 'Clear Unknown Formatting' );
+		expect( await editor.getEditedPostContent() ).toBe(
+			`<!-- wp:paragraph -->
+<p>test</p>
 <!-- /wp:paragraph -->`
 		);
 	} );