Example plugin adding custom taxonomies to web stories.

web-stories-taxonomy-example.php

<?php
/**
 * Plugin Name: Web Stories Taxonomy Example
 * Description: Example plugin adding custom taxonomies to web stories.
 * Plugin URI: https://wp.stories.google/
 * Author: Pascal Birchler, Google
 * Author URI: https://opensource.google.com/
 * Version: 0.0.1
 * License: Apache License 2.0
 * License URI: https://www.apache.org/licenses/LICENSE-2.0
 */

add_action(
	'init',
	static function () {
		register_taxonomy(
            'story-tag',
            'web-story',
            [
                'description'  => 'Story Tags',
                'show_in_rest' => true,
                'rest_base'    => 'story-tags',
            ]
        );

        register_taxonomy(
            'story-color',
            'web-story',
            [
                'description'  => 'Story Colors',
                'show_in_rest' => true,
                'rest_base'    => 'story-colors',
                'labels'       => [
                    'name'                       => 'Colors',
                    'singular_name'              => 'Color',
                    'search_items'               => 'Search Colors',
                    'popular_items'              => 'Popular Colors',
                    'all_items'                  => 'All Colors',
                    'edit_item'                  => 'Edit Color',
                    'view_item'                  => 'View Color',
                    'update_item'                => 'Update Color',
                    'add_new_item'               => 'Add New Color',
                    'new_item_name'              => 'New Color Name',
                    'separate_items_with_commas' => 'Separate colors with commas',
                    'add_or_remove_items'        => 'Add or remove colors',
                    'choose_from_most_used'      => 'Choose from the most used colors',
                    'not_found'                  => 'No colors found.',
                    'no_terms'                   => 'No colors',
                    'items_list_navigation'      => 'Colors list navigation',
                    'items_list'                 => 'Colors list',
                    'most_used'                  => 'Most Used',
                    'back_to_items'              => '&larr; Go to Colors',
                    'item_link'                  => 'Color Color',
                    'item_link_description'      => 'A link to a color.',
                ],
            ]
        );

        register_taxonomy(
            'story-category',
            'web-story',
            [
                'description'  => 'Story Categories',
                'hierarchical' => true,
                'show_in_rest' => true,
                'rest_base'    => 'story-categories',
            ]
        );

        register_taxonomy(
            'story-vertical',
            'web-story',
            [
                'description'  => 'Story Verticals',
                'hierarchical' => true,
                'show_in_rest' => true,
                'rest_base'    => 'story-verticals',
                'labels'       => [
                    'name'                       => 'Verticals',
                    'singular_name'              => 'Vertical',
                    'search_items'               => 'Search Verticals',
                    'all_items'                  => 'All Verticals',
                    'parent_item'                => 'Parent Vertical',
                    'parent_item_colon'          => 'Parent Vertical:',
                    'edit_item'                  => 'Edit Vertical',
                    'view_item'                  => 'View Vertical',
                    'update_item'                => 'Update Vertical',
                    'add_new_item'               => 'Add New Vertical',
                    'new_item_name'              => 'New Vertical Name',
                    'not_found'                  => 'No verticals found.',
                    'no_terms'                   => 'No verticals',
                    'filter_by_item'             => 'Filter by vertical',
                    'items_list_navigation'      => 'Verticals list navigation',
                    'items_list'                 => 'Verticals list',
                    'most_used'                  => 'Most Used',
                    'back_to_items'              => '&larr; Go to Verticals',
                    'item_link'                  => 'Color Vertical',
                    'item_link_description'      => 'A link to a vertical.',
                ],
            ]
        );
	}
);