Extension name : phpList
Allows for subscribing a user to your instalment of PHPList. ( https://www.phplist.org )
PHPList needs a name and an email address as a bare minimum, so a form should provide that information.
All the other configuration settings can be done inside the PostHandler PHP file. ( FlexForm/src/Modules/Handlers/phpList/PostHandler.php )
private const HTML = 1;
private const PHP_LIST_URL = '<nowiki>https://nwi.wikibase.nl/lists'</nowiki>;
private const FIELD_EMAIL = 'email';
private const FIELD_NAME = 'name';
private const FIELD_AS_EMAIL = 'useFieldAsEmail';
private const FIELD_AS_NAME = 'useFieldAsName';
private const DEFAULT_LISTS = [
3 => 'signup',
4 => 'signup',
5 => 'signup',
6 => 'signup',
7 => 'signup',
8 => 'signup'
];