In Drupal 8 I have a custom comment type and when I use the default core comment.html.twig to render the comments then variables like 'new_indicator_timestamp' and 'parent' get rendered as expected. But if I switch to using a custom layout (via layout_plugin and display suite) and copy across the relevant twig template code for those core comment preprocess variables into my own custom layout then they don't work.
What do I need to do to ensure that the comment.module template_preprocess_comment()
variables are available to my custom comment layout?