In 9.2 and below \Drupal\Core\Entity\EntityBase::getTypedData would only call the default \Drupal\Core\Entity\Plugin\DataType\EntityAdapter::createFromEntity plugin to create the typed data.
This meant that every entity-type that wanted to provide an alternate implementation of \Drupal\Core\Entity\Plugin\DataType\EntityAdapter::createFromEntity would need to sub-class \Drupal\Core\Entity\EntityBase::getTypedData and provide an alternate implementation.
From 9.3.0 \Drupal\Core\Entity\EntityBase::getTypedData will use the specific entity-type (and bundle if applicable) typed-data plugin when calling \Drupal\Core\Entity\Plugin\DataType\EntityAdapter::createFromEntity
This means that modules that alter the typed-data plugin definitions for a specific entity type or bundle, can now also provide an implementation of \Drupal\Core\Entity\Plugin\DataType\EntityAdapter::createFromEntity and it will be called.
