Course format API deprecation messages incorrect

The updated Course format API (https://docs.moodle.org/dev/Moodle_4.0_developer_update#The_core_courseformat_subsystem), has lead to methods being deprecated, however, the 'debugging' messages, such as:

debugging('section_left_content() can not be used anymore. Please use ' .
'core_course\output\section_format to render a section.', DEBUG_DEVELOPER);

in /course/format/classes/output/section_render.php refer to non-existant classes!  Even /course/format/classes/output/local/content/section/cmitem.php has:

use core_course\output\section_format;

This is on 4.0dev+ (Build: 20211022).