$ app/console container:debug | grep mail
 project.admin.mailer                                           container Project\Admin\AdminBundle\Service\MailerService

 project.mailer                                                 container Project\MainBundle\Mailer\Mailer

 form.type.email                                                 container Symfo
ny\Component\Form\Extension\Core\Type\EmailType

 fos_user.mailer                                                 container FOS\U
serBundle\Mailer\Mailer

 fos_user.util.email_canonicalizer                               container FOS\U
serBundle\Util\Canonicalizer

 fos_user.util.username_canonicalizer                            n/a       alias
 for "fos_user.util.email_canonicalizer"

 mailer                                                          n/a       alias
 for "swiftmailer.mailer.default"

 manager.mailer.partners                                         container Project\PartnersBundle\Manager\MailerPartners

 swiftmailer.email_sender.listener                               container Symfo
ny\Bundle\SwiftmailerBundle\EventListener\EmailSenderListener

 swiftmailer.mailer                                              n/a       alias
 for "swiftmailer.mailer.default"

 swiftmailer.mailer.default                                      container Swift
_Mailer

 swiftmailer.mailer.default.plugin.messagelogger                 container Swift
_Plugins_MessageLogger

 swiftmailer.mailer.default.spool                                container Swift
_MemorySpool

 swiftmailer.mailer.default.transport                            container Swift
_Transport_SpoolTransport

 swiftmailer.mailer.default.transport.real                       container Swift
_Transport_EsmtpTransport

 swiftmailer.plugin.messagelogger                                n/a       alias
 for "swiftmailer.mailer.default.plugin.messagelogger"

 swiftmailer.spool                                               n/a       alias
 for "swiftmailer.mailer.default.spool"

 swiftmailer.transport                                           n/a       alias
 for "swiftmailer.mailer.default.transport"

 swiftmailer.transport.real                                      n/a       alias
 for "swiftmailer.mailer.default.transport.real"