Drupal Core APIs

Request object

DrupalKernel object.
createFromRequest accepts a Request object for use in intializeSettings

Settings object.
Database static method

Kernel handle() does initializeSettings(Request $request) and boot()

DrupalKernel very important service container property, which holds all Drupal services, and notably the http_kernel service, which gives us

Old fashioned ...
GLOBAL $config variable and require statement for settings.php
a $databases array passed to a Database static method.
a $settings array passed to Settings object.

drush ev 'print \Drupal::keyValue("system.schema")->get("crystalbit_entity_updates") . "\n";'
drush ev "\Drupal::keyValue('system.schema')->set('crystalbit_entity_updates', (int) 11102)";