`Services.yaml`

Services can be configured in this file. TYPO3 uses it for:

Dependency Injection
Event Listeners
Command Controllers (see Feature: #89139 - Add dependency injection support for console commands)
Registering a widget with the dashboard

EXT:my_extension/Configuration/Services.yaml

services:
  _defaults:
    autowire: true
    autoconfigure: true
    public: false

  T3docs\Examples\:
    resource: '../Classes/*'
    exclude: '../Classes/Domain/Model/*'

  MyVendor\MyExtension\LinkValidator\LinkType\ExampleLinkType:
    tags:
      -  name: linkvalidator.linktype