#SUPPORT_EMAIL: '%env(SUPPORT_EMAIL)%'
# config/packages/dev/mailer.yaml
framework:
  mailer:
    envelope:
      sender: 'fabien@example.com'
      recipients: ['foo@example.com', 'bar@example.com']
    headers:
      from: '%env(SUPPORT_EMAIL)%'
      bcc: 'baz@example.com'
      X-Custom-Header: 'foobar'