diff --git a/wp-admin/edit-form-blocks.php b/wp-admin/edit-form-blocks.php
index 8fdea59a18..a842facd49 100644
--- a/wp-admin/edit-form-blocks.php
+++ b/wp-admin/edit-form-blocks.php
@@ -209,6 +209,10 @@ $editor_settings = array(
 	'enableCustomFields'   => (bool) get_user_meta( get_current_user_id(), 'enable_custom_fields', true ),
 );
 
+// Add additional back-compat patterns registered by `current_screen` et al.
+$editor_settings['__experimentalAdditionalBlockPatterns']          = WP_Block_Patterns_Registry::get_instance()->get_all_registered( true );
+$editor_settings['__experimentalAdditionalBlockPatternCategories'] = WP_Block_Pattern_Categories_Registry::get_instance()->get_all_registered( true );
+
 $autosave = wp_get_post_autosave( $post->ID );
 if ( $autosave ) {
 	if ( mysql2date( 'U', $autosave->post_modified_gmt, false ) > mysql2date( 'U', $post->post_modified_gmt, false ) ) {
diff --git a/wp-admin/site-editor.php b/wp-admin/site-editor.php
index 317660909c..9fac7e62c7 100644
--- a/wp-admin/site-editor.php
+++ b/wp-admin/site-editor.php
@@ -68,6 +68,11 @@ $custom_settings      = array(
 	'defaultTemplatePartAreas' => get_allowed_block_template_part_areas(),
 	'__unstableHomeTemplate'   => $home_template,
 );
+
+// Add additional back-compat patterns registered by `current_screen` et al.
+$custom_settings['__experimentalAdditionalBlockPatterns']          = WP_Block_Patterns_Registry::get_instance()->get_all_registered( true );
+$custom_settings['__experimentalAdditionalBlockPatternCategories'] = WP_Block_Pattern_Categories_Registry::get_instance()->get_all_registered( true );
+
 $editor_settings      = get_block_editor_settings( $custom_settings, $block_editor_context );
 
 if ( isset( $_GET['postType'] ) && ! isset( $_GET['postId'] ) ) {
diff --git a/wp-includes/class-wp-block-pattern-categories-registry.php b/wp-includes/class-wp-block-pattern-categories-registry.php
index b223dbf4a2..f4d881c4e2 100644
--- a/wp-includes/class-wp-block-pattern-categories-registry.php
+++ b/wp-includes/class-wp-block-pattern-categories-registry.php
@@ -19,6 +19,14 @@ final class WP_Block_Pattern_Categories_Registry {
 	 */
 	private $registered_categories = array();
 
+	/**
+	 * Pattern categories registered outside the `init` action.
+	 *
+	 * @since 6.0.0
+	 * @var array[]
+	 */
+	private $registered_categories_outside_init = array();
+
 	/**
 	 * Container for the main instance of the class.
 	 *
@@ -50,11 +58,20 @@ final class WP_Block_Pattern_Categories_Registry {
 			return false;
 		}
 
-		$this->registered_categories[ $category_name ] = array_merge(
+		$category = array_merge(
 			array( 'name' => $category_name ),
 			$category_properties
 		);
 
+		$this->registered_categories[ $category_name ] = $category;
+
+		// If the category is registered inside an action other than `init`, store it
+		// also to a dedicated array. Used to detect deprecated registrations inside
+		// `admin_init` or `current_screen`.
+		if ( current_action() && 'init' !== current_action() ) {
+			$this->registered_categories_outside_init[ $category_name ] = $category;
+		}
+
 		return true;
 	}
 
@@ -78,6 +95,7 @@ final class WP_Block_Pattern_Categories_Registry {
 		}
 
 		unset( $this->registered_categories[ $category_name ] );
+		unset( $this->registered_categories_outside_init[ $category_name ] );
 
 		return true;
 	}
@@ -103,10 +121,15 @@ final class WP_Block_Pattern_Categories_Registry {
 	 *
 	 * @since 5.5.0
 	 *
+	 * @param bool $outside_init_only Return only categories registered outside the `init` action.
 	 * @return array[] Array of arrays containing the registered pattern categories properties.
 	 */
-	public function get_all_registered() {
-		return array_values( $this->registered_categories );
+	public function get_all_registered( $outside_init_only = false ) {
+		return array_values(
+			$outside_init_only
+				? $this->registered_categories_outside_init
+				: $this->registered_categories
+		);
 	}
 
 	/**
diff --git a/wp-includes/class-wp-block-patterns-registry.php b/wp-includes/class-wp-block-patterns-registry.php
index e08d10bc28..81ee2e261c 100644
--- a/wp-includes/class-wp-block-patterns-registry.php
+++ b/wp-includes/class-wp-block-patterns-registry.php
@@ -21,6 +21,14 @@ final class WP_Block_Patterns_Registry {
 	 */
 	private $registered_patterns = array();
 
+	/**
+	 * Patterns registered outside the `init` action.
+	 *
+	 * @since 6.0.0
+	 * @var array[]
+	 */
+	private $registered_patterns_outside_init = array();
+
 	/**
 	 * Container for the main instance of the class.
 	 *
@@ -92,10 +100,18 @@ final class WP_Block_Patterns_Registry {
 			return false;
 		}
 
-		$this->registered_patterns[ $pattern_name ] = array_merge(
+		$pattern = array_merge(
 			$pattern_properties,
 			array( 'name' => $pattern_name )
 		);
+		$this->registered_patterns[ $pattern_name ] = $pattern;
+
+		// If the pattern is registered inside an action other than `init`, store it
+		// also to a dedicated array. Used to detect deprecated registrations inside
+		// `admin_init` or `current_screen`.
+		if ( current_action() && 'init' !== current_action() ) {
+			$this->registered_patterns_outside_init[ $pattern_name ] = $pattern;
+		}
 
 		return true;
 	}
@@ -120,6 +136,7 @@ final class WP_Block_Patterns_Registry {
 		}
 
 		unset( $this->registered_patterns[ $pattern_name ] );
+		unset( $this->registered_patterns_outside_init[ $pattern_name ] );
 
 		return true;
 	}
@@ -145,11 +162,16 @@ final class WP_Block_Patterns_Registry {
 	 *
 	 * @since 5.5.0
 	 *
+	 * @param bool $outside_init_only Return only patterns registered outside the `init` action.
 	 * @return array[] Array of arrays containing the registered block patterns properties,
 	 *                 and per style.
 	 */
-	public function get_all_registered() {
-		return array_values( $this->registered_patterns );
+	public function get_all_registered( $outside_init_only = false ) {
+		return array_values(
+			$outside_init_only
+				? $this->registered_patterns_outside_init
+				: $this->registered_patterns
+		);
 	}
 
 	/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index ef91d91b62..5f01ab0704 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-53403';
+$wp_version = '6.1-alpha-53404';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.