Currently, the extending process gets refactored. Please don't use it in productive projects.
The recommended way to install TYPO3 Console is by using Composer:
composer require evoweb/extender
Add the extending classname to your packages Services.yaml and add a tag to it. The tag must contain the name 'extender.extends' and the class it is extending.
Services.yaml
services:
Fixture\ExtendingExtension\Domain\Model\BlobExtend:
tags:
-
name: 'extender.extends'
class: Fixture\BaseExtension\Domain\Model\Blob