taxonomy registration

[carstingaxion]

Since Gutenberg 13.3 (and WP 6.1), a post term block variation is generated for each registered custom taxonomy. For example, if you register a “Product category” taxonomy, you should able to add a “Product categories” block that lists all the product category terms assigned to the current post.

But, currently, for the post term block variation automatic generation to work you need to register the custom taxonomies earlier in the process (a priority lower than 10).

Example: add_action( 'init', 'wpdocs_register_taxonomies', 9 );

https://developer.wordpress.org/reference/functions/register_taxonomy/#comment-6850