Overview of the Dependency Injection Container and Services. Overview of container, injection, and services The

Service tags overview Some services have tags, which are defined in the service definition. Tags are used to define a group of related services

API for describing data based on a set of available data types. PHP has data types, such as int, string, float, array, etc., and it is an object-oriented

hook_mail($key, &$message, $params) Prepares a message based on parameters; This

Overview of standards and best practices for developers Ideally, all code that is included in Drupal Core and contributed modules, themes, and

hook_queue_info_alter(&$queues) Alter cron queue information before cron runs. Called

Overview of utility classes and functions for developers. Drupal provides developers with a variety of utility functions that make it easier

hook_countries_alter(&$countries) Alter the default country list. Parameters

Information about the Configuration API. The Configuration API is one of several methods in Drupal for storing information. See the

Annotations for class discovery and metadata description. The Drupal plugin system has a set of reusable components that developers can use