Magento System/Data Transfer/Export, where Magento defines the data of exported files?

I searched and found that the export was executed by a corn job, and I think the file that was executed in the process is “MagentoImportExportModelExportConsumer::process” but I add a die() at the beginning of the file and the export was successful, I want to know where the data is set exactly or how can I log errors while working with cron.