I have a site with "EN-US" as default language. This language is not supported on localize.drupal.org. I am unable to use "drush site-install --existing-config" because it triggers an InstallerException
In install.core.inc line 2345: [Drupal\Core\Installer\Exception\InstallerException] Translation:The en-us translation is not available.
The en-us translation file is not available at the translation server. Choose a different language → or select English and translate your website later.
Active
11.2 🔥
install system
In Drupal core changes are made on on 11.x (our main development branch) first, and are then back ported as needed according to the Core change policies → . Also mentioned on the version → section of the list of issue fields documentation.