I have a plugin that hooks into the classic editor in a whole heap of ways so I’ll have to create and maintain separate code for Gutenberg and keep the existing code for those who won’t use Gutenberg. In WP 4.9.8, the post editor (admin/post.php or admin/post-new.php) is called with a query parameter of “classic-editor” if the classic editor is to be used.
Any idea if this is something we can rely on in future releases to determine which editor is going to be used?