In reply to David Artiss.

Hi David,

I was aware of all this. Currently you can use add_filter( 'gutenberg_can_edit_post_type', '__return_false' ); with WordPress 4.9 in the functions.php file to disable Gutenberg, no need for a plugin.

Indeed TinyMCE will continue to be part of core but it is not clear if that includes the the whole backend interface for editing posts, warts and all (metaboxes). On the filter mentioned above you really have to dig deep with the staff supporting Gutenberg if any of this is the case. I have been told on support tickets that the filter would be renamed or a new filter provided once Gutenberg is included in core and effectively would work as before. WordPress 5 beta is now available but I don't see a replacement filter that will disable Gutenberg.

On who actually makes Gutenberg, I don't think it really matters from my point of view as an end user. I was only letting people know, if they wanted to use test the beta the only option at the moment is the Classic Editor plugin if you need to disable Gutenberg. In the long run we will have to deal with whatever option is available to work with or disable Gutenberg. Knowing what those options are going to be would be very helpful for those of us who need to continue working with the current editor.