Ticket #51258: 51258.diff

src/wp-admin/post-new.php

@@ -78 +78 @@
         // Flag that we're not loading the block editor.
         $current_screen = get_current_screen();
         $current_screen->is_block_editor( false );
+
+        /** This filter is documented in wp-admin/post-new.php */
+        do_action( 'replaced_editor', $post );
 }
 
 require_once ABSPATH . 'wp-admin/admin-footer.php';

src/wp-admin/post.php

@@ -180 +180 @@
                  * @param WP_Post $post    Post object.
                  */
                 if ( true === apply_filters( 'replace_editor', false, $post ) ) {
+                        /**
+                         * Fires when a replacement editor is expected to load.
+                         *
+                         * @since 5.6.0
+                         *
+                         * @param WP_Post $post The post that is being edited.
+                         */
+                        do_action( 'replaced_editor', $post );
+
                         break;
                 }