editorjs-2.x-dev/modules/prism/editorjs_prism.module

<?php

/**
 * @file
 * Primary module hooks for "editorjs_prism" module.
 */

/**
 * Implements hook_theme().
 */
function editorjs_prism_theme() {
  return [
    'ce_block__prism_code' => [
      'base hook' => 'ce_block',
    ],
  ];
}

/**
 * Implements hook_preprocess_HOOK().
 *
 * Prepare variables for "ce_block__prism_code" template.
 */
function template_preprocess_ce_block__prism_code(&$variables) {
  $code = $variables['data']['languageCode'] ?? FALSE;
  if ($code) {
    $variables['#attached']['library'][] = "editorjs_prism/{$code}";
  }
}