Length limit of the configuration entity prefix.
Configuration entity names are composed of two parts:
The config prefix, which is returned by getConfigPrefix() and is composed of: The provider module name (limited to 50 characters by DRUPAL_EXTENSION_NAME_MAX_LENGTH). The module-specific namespace identifier, which defaults to the configuration entity type ID. Entity type IDs are limited to 32 characters by EntityTypeInterface::ID_MAX_LENGTH. The configuration entity ID.
So, a typical confi