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function block_core_navigation_get_fallback_blocks() {
	$page_list_fallback = array(
		array(
			'blockName'    => 'core/page-list',
			'innerContent' => array(),
			'attrs'        => array(),
		),
	);

	$registry = WP_Block_Type_Registry::get_instance();

	// If `core/page-list` is not registered then return empty blocks.
	$fallback_blocks = $registry->is_registered( 'core/page-list' ) ? $page_list_fallback : array();
	$navigation_post = WP_Navigation_Fallback::get_fallback();

	// Use the first non-empty Navigation as fallback if available.
	if ( $navigation_post ) {
		$parsed_blocks  = parse_blocks( $navigation_post->post_content );
		$maybe_fallback = block_core_navigation_filter_out_empty_blocks( $parsed_blocks );

		// Normalizing blocks may result in an empty array of blocks if they were all `null` blocks.
		// In this case default to the (Page List) fallback.
		$fallback_blocks = ! empty( $maybe_fallback ) ? $maybe_fallback : $fallback_blocks;

		// Run Block Hooks algorithm to inject hooked blocks.
		// We have to run it here because we need the post ID of the Navigation block to track ignored hooked blocks.
		$markup = block_core_navigation_insert_hooked_blocks( $fallback_blocks, $navigation_post );
		$blocks = parse_blocks( $markup );

		if ( isset( $blocks[0]['innerBlocks'] ) ) {
			$fallback_blocks = $blocks[0]['innerBlocks'];
		}
	}

	/**
	 * Filters the fallback experience for the Navigation block.
	 *
	 * Returning a falsey value will opt out of the fallback and cause the block not to render.
	 * To customise the blocks provided return an array of blocks - these should be valid
	 * children of the `core/navigation` block.
	 *
	 * @since 5.9.0
	 *
	 * @param array[] $fallback_blocks default fallback blocks provided by the default block mechanic.
	 */
	return apply_filters( 'block_core_navigation_render_fallback', $fallback_blocks );
}