The sender name is defined in MailServiceProvider
You could override the value by using the following code in your local extend.php:
<?php
use Flarum\Extend;
return [
new Extend\Compat(function(\Flarum\Foundation\Application $app) {
$app->afterResolving('mailer', function ($mailer) use ($app) {
$settings = $app->make(\Flarum\Settings\SettingsRepositoryInterface::class);
$mailer->alwaysFrom($settings->get('mail_from'), $settings->get('forum_title'));
});
}),
];
You could replace the second argument to alwaysFrom with a hard-coded string, or a value pulled from somewhere else. By default it uses the forum title.
To modify the subject of emails, you could use the Linguist extension to customize the translations. This however won't allow changing the prefix applied to each title with the forum name. Changing that is complicated because you need to either extend/override each individual part of the code that sends email, or replace the Mailer with your own implementation that substitutes a title with another.
