I have wasted several hours on the “Create Block Theme” plugin. Now it’s imposible to add new fonts. This error will come up:

I have filed an error report to WP. The error suggests that you should add something along these lines to wp_config.php. But this has no effect on the plugin.

# define( 'DISALLOW_FILE_EDIT', false );

Now adding fonts to a theme that calls itself “Full Site Editing” should work like a breeze. In reality it’s a stumbling block.

WordPress 6.3 has high ambitions, but honestly speaking, but in practise the UX is too often confusion. So this is perhaps a minor problem.