A preliminary reading: The default implementation of the \Psr\Log\LoggerInterface
is \Magento\Framework\Logger\Monolog
.
https://github.com/Seldaek/monolog/blob/1.16.0/src/Monolog/Logger.php#L582-L594
https://github.com/Seldaek/monolog/blob/1.16.0/src/Monolog/Logger.php#L59-L64
Further reading: How does \Magento\Framework\Logger\Monolog::addRecord()
work?