Authenticated cron entry point for web request.
To let external service initiate cron tasks having authenticated entry point helps. vtigercron.php restricts execution from CLI or when there is active authenticated session.
NOTE: CRON tasks can be heavy at times (both memory and time hungry). Request initiated through web could will get terminated if max_execution_time or memory_limit cap enforced by Server configuration. Due to this reason this enhancement is not being plugged into the core product.