As with PhoneNumberUtil, the Phone Number Carrier Mapper uses a singleton.
$carrierMapper = \libphonenumber\PhoneNumberToCarrierMapper::getInstance();
getNameForNumber()Returns the name of the carrier for the supplied PhoneNumber object within the $language supplied.
$chNumber = \libphonenumber\PhoneNumberUtil::getInstance()->parse("798765432", "CH");
var_dump($carrierMapper->getNameForNumber($chNumber, 'en'));
// string(8) "Swisscom"
getNameForValidNumber()Returns the same as getNameForNumber() without checking whether it is a valid number for carrier mapping.
getSafeDisplayName()Returns the same as getNameForNumber(), but only if the number is safe for carrier mapping. A number is only validate for carrier mapping if it’s a Mobile or Fixed line, and the country does not support Mobile Number Portability.