What is the difference between the config and the settings directories?

Question

I can see a folder named config in Drupal 8 core modules which contains sub directories like optional, schema and install.

I can see it is like a settings folder which is initialised during module installation. But how do they differ from each other?

Answer 1

• schema
  This folder is used for schema related things. This is most often used to tell Drupal how custom configurations and configuration entities will be saved.
• install
  The folder can contain configurations, for example a view. All configurations will be installed; if any configuration fails, the module can't be installed.
• optional
  The folder can contain configurations, for example a view. All configurations will be installed if possible. If a configuration has missing dependencies, it won't be installed.

Configuration installation only happens when the module itself is installed. Optional configurations can install missing configurations when dependencies are met by a new installed module.