Absolute Free Architecture-Specialist Exam Practice for Comprehensive Preparation 

Isolated Business Logic (Actions) or Core Widgets (blocks), to manage complexity, composition or to have its own lifecycle.

A BL becomes a Calculation Engine if it performs complex calculations, (e.g. an invoice calculation engine or an insurance simulator). Engines are usually subject to versions. 

Logic to Synchronize data in CS's with an external system. Isolating this logic makes the CS completely system agnostic and it's easier to decouple or replace the external system.

Technical wrapper to expose an API to External consumers, keeping core services system agnostic and supporting multiple versions of the API.

Works on the client side and adds verification of the server certificate against hashes of public keys, which are pre-bundled with the mobile app 

Discovery automatically assigns a module to an Architecture Canvas layer, following the module's naming convention. 

Discovery allows you to determine for every module, which elements are being consumed by other modules.