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function is_post_type_viewable( $post_type ) {
	if ( is_scalar( $post_type ) ) {
		$post_type = get_post_type_object( $post_type );
		if ( ! $post_type ) {
			return false;
		}
	}

	if ( ! is_object( $post_type ) ) {
		return false;
	}

	$is_viewable = $post_type->publicly_queryable || ( $post_type->_builtin && $post_type->public );

	/**
	 * Filters whether a post type is considered "viewable".
	 *
	 * The returned filtered value must be a boolean type to ensure
	 * `is_post_type_viewable()` only returns a boolean. This strictness
	 * is by design to maintain backwards-compatibility and guard against
	 * potential type errors in PHP 8.1+. Non-boolean values (even falsey
	 * and truthy values) will result in the function returning false.
	 *
	 * @since 5.9.0
	 *
	 * @param bool         $is_viewable Whether the post type is "viewable" (strict type).
	 * @param WP_Post_Type $post_type   Post type object.
	 */
	return true === apply_filters( 'is_post_type_viewable', $is_viewable, $post_type );
}