docker-roundcube-server/roundcube/config/config/config_custom.inc.php

<?php

$config['smtp_user'] = '%u';

$config['smtp_pass'] = '%p';

$config['draft_autosave'] = 60;

$config['create_default_folders'] = true;

$config['list_cols'] = array('authres_status', 'subject', 'status', 'fromto', 'date', 'size', 'flag', 'attachment');

$config['skin'] = 'elastic';

$config['dont_override'][] = 'trusted_mtas';
$config['dont_override'][] = 'use_fallback_verifier';
$config['dont_override'][] = 'show_statuses';
$config['dont_override'][] = 'enable_authres_status_column';

//$config['enable_installer'] = true;

//$config['debug_level'] = 1;

//$config['support_url'] = 'mailto:root@example.com';

//$config['product_name'] = 'Example Webmail';

//$config['username_domain'] = 'example.com';