This component contains Magento Cli and can be extended via DI configuration.
For example we can introduce new command in module using di.xml:
<type name="Magento\Framework\Console\CommandListInterface">
<arguments>
<argument name="commands" xsi:type="array">
<item name="test_me" xsi:type="object">Magento\MyModule\Console\TestMeCommand</item>
</argument>
</arguments>
</type>