Now when calling $TSFE->set_no_cache(), a reason can be provided and logged, making it easier to find why cache was disabled on a page.
Ex:
$TSFE->set_no_cache(‘Reached an unstable condition in extension xyz’);
More info:
Fix #11669: Provide a reason for why $TSFE->set_no_cache() has been triggered
http://bugs.typo3.org/view.php?id=11669