Feature: #98394 - Introduce event to prevent downloading of language packs

See forge#98394

Description

EXT:my_extension/Configuration/Services.yaml
services:
  MyVendor\MyExtension\EventListener\ModifyLanguagePacks:
    tags:
      - name: event.listener
        identifier: 'modifyLanguagePacks'
        event: TYPO3\CMS\Install\Service\Event\ModifyLanguagePacksEvent
        method: 'modifyLanguagePacks'
EXT:my_extension/Classes/EventListener/ModifyLanguagePacks.php
<?php
namespace MyVendor\MyExtension\EventListener;

use TYPO3\CMS\Install\Service\Event\ModifyLanguagePacksEvent;

final class ModifyLanguagePacks
{
    public function modifyLanguagePacks(ModifyLanguagePacksEvent $event): void
    {
        $extensions = $event->getExtensions();
        foreach ($extensions as $key => $extension){
            if($extension['type'] === 'typo3-cms-framework'){
                $event->removeExtension($key);
            }
        }
        $event->removeIsoFromExtension('de', 'styleguide');
    }
}

Impact

With the newly introduced event, it is possible to ignore extensions or individual language packs for extensions when downloading the language packs. However, only language packs for extensions and languages available in the system can be downloaded. The options of the language:update command can be used to further restrict the download (ignore additional extensions or download only specific languages), but not to ignore decisions made by the event.