From e241f5a9c1705fdc4ca096599105fbef699478d6 Mon Sep 17 00:00:00 2001
From: Aki Hamano <tetsuaki.hamano@gmail.com>
Date: Mon, 19 Jan 2026 21:33:59 +0900
Subject: [PATCH] Make format control restrictions experimental

---
 lib/experimental/editor-settings.php                 |  3 +++
 lib/experiments-page.php                             | 12 ++++++++++++
 .../block-editor/src/components/rich-text/index.js   |  4 +++-
 .../src/components/rich-text/use-format-types.js     |  8 +++++++-
 .../src/hooks/block-fields/rich-text/index.js        |  3 ++-
 5 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/lib/experimental/editor-settings.php b/lib/experimental/editor-settings.php
index 3823ae58ea660e..62529fcad8bddd 100644
--- a/lib/experimental/editor-settings.php
+++ b/lib/experimental/editor-settings.php
@@ -49,6 +49,9 @@ function gutenberg_enable_experiments() {
 	if ( gutenberg_is_experiment_enabled( 'gutenberg-media-editor' ) ) {
 		wp_add_inline_script( 'wp-block-editor', 'window.__experimentalMediaEditor = true', 'before' );
 	}
+	if ( gutenberg_is_experiment_enabled( 'gutenberg-restrict-formatting-in-content-only-mode' ) ) {
+		wp_add_inline_script( 'wp-block-editor', 'window.__experimentalRestrictFormattingInContentOnlyMode = true', 'before' );
+	}
 }
 
 add_action( 'admin_init', 'gutenberg_enable_experiments' );
diff --git a/lib/experiments-page.php b/lib/experiments-page.php
index 6832a305848b1f..d29b74356c1439 100644
--- a/lib/experiments-page.php
+++ b/lib/experiments-page.php
@@ -258,6 +258,18 @@ function gutenberg_initialize_experiments_settings() {
 		)
 	);
 
+	add_settings_field(
+		'gutenberg-restrict-formatting-in-content-only-mode',
+		__( 'Restrict formatting controls in Content Only mode', 'gutenberg' ),
+		'gutenberg_display_experiment_field',
+		'gutenberg-experiments',
+		'gutenberg_experiments_section',
+		array(
+			'label' => __( 'Restricts RichText formatting controls when in Content Only mode to provide a simpler, more focused editing experience while maintaining essential content functionality.', 'gutenberg' ),
+			'id'    => 'gutenberg-restrict-formatting-in-content-only-mode',
+		)
+	);
+
 	register_setting(
 		'gutenberg-experiments',
 		'gutenberg-experiments'
diff --git a/packages/block-editor/src/components/rich-text/index.js b/packages/block-editor/src/components/rich-text/index.js
index 52de9bb69d63a2..02e510ab29d33e 100644
--- a/packages/block-editor/src/components/rich-text/index.js
+++ b/packages/block-editor/src/components/rich-text/index.js
@@ -352,7 +352,9 @@ export function RichTextWrapper(
 		identifier,
 		allowedFormats: adjustedAllowedFormats,
 		withoutInteractiveFormatting,
-		disableNoneEssentialFormatting: isContentOnly,
+		disableNoneEssentialFormatting:
+			isContentOnly &&
+			window?.__experimentalRestrictFormattingInContentOnlyMode,
 	} );
 
 	function addEditorOnlyFormats( value ) {
diff --git a/packages/block-editor/src/components/rich-text/use-format-types.js b/packages/block-editor/src/components/rich-text/use-format-types.js
index f6d55ea1cb9644..8dda027939ecc4 100644
--- a/packages/block-editor/src/components/rich-text/use-format-types.js
+++ b/packages/block-editor/src/components/rich-text/use-format-types.js
@@ -67,6 +67,8 @@ function getPrefixedSelectKeys( selected, prefix ) {
  * @param {Array}   options.allowedFormats                 Allowed formats
  * @param {boolean} options.withoutInteractiveFormatting   Whether to clean the interactive formatting or not.
  * @param {boolean} options.disableNoneEssentialFormatting Whether to disable none-essential formatting or not.
+ *                                                         This option is pnly available when "Restrict formatting
+ *                                                         controls in Content Only mode" experimental setting is enabled.
  */
 export function useFormatTypes( {
 	clientId,
@@ -88,7 +90,11 @@ export function useFormatTypes( {
 					return false;
 				}
 
-				if ( disableNoneEssentialFormatting && ! isEssential ) {
+				if (
+					disableNoneEssentialFormatting &&
+					! isEssential &&
+					window?.__experimentalRestrictFormattingInContentOnlyMode
+				) {
 					return false;
 				}
 
diff --git a/packages/block-editor/src/hooks/block-fields/rich-text/index.js b/packages/block-editor/src/hooks/block-fields/rich-text/index.js
index b019909138963d..9c695ae9d4ff5a 100644
--- a/packages/block-editor/src/hooks/block-fields/rich-text/index.js
+++ b/packages/block-editor/src/hooks/block-fields/rich-text/index.js
@@ -58,7 +58,8 @@ export default function RichTextControl( {
 		identifier: field.id,
 		allowedFormats: adjustedAllowedFormats,
 		withoutInteractiveFormatting: fieldConfig?.withoutInteractiveFormatting,
-		disableNoneEssentialFormatting: true,
+		disableNoneEssentialFormatting:
+			window?.__experimentalRestrictFormattingInContentOnlyMode,
 	} );
 
 	function addEditorOnlyFormats( value ) {