Where do I fetch myself complete definition for a bundle?
To get the language specific configuration of a bundle use ContentLanguageSettings::loadByEntityTypeBundle.

For the translatability of the bundle, you'd use:

$settings = ContentLanguageSettings::loadByEntityTypeBundle($entity_type_id, $bundle_name);
$isBundleTranslatable = $settings-&gt;getThirdPartySetting("content_translation", "enabled");


You could also use ContentTranslationManager:

/** @var ContentTranslationManager $contentTranslationManager */
$contentTranslationManager = \Drupal::service('content_translation.manager');
$isBundleTranslatable = $contentTranslationManager-&gt;isEnabled($entity_type_id, $bundle_name);