I have a WordPress site that has some pages created/edited in Classic Editor, and some pages that built/edited with Gutenberg/Block Editor. I am trying to create a report of which pages use each editor. Is there a meta value that tracks which editor was used to edit a post?
Check the post type support for editors
post_type_supports($post_type, 'editor'); For classic editor gutenberg_can_edit_post_type( $post_type ); or use_block_editor_for_post_type( $post_type ); to check the block editor support.
Next create a meta key and change its value to the choice of editor (every time you choose to change the editor.)
'classic_editor_enabled_editors_for_post' you can use this filter if you are using the classic editor plugin.