Important: #105703 - Premature end of script headers due to X-TYPO3-Cache-Tags

See forge#105703

Description

The X-TYPO3-Cache-Tags header is now split into multiple lines if it exceeds the maximum of 8000 characters. This change prevents premature end of script headers and ensures that the header is sent correctly, even if it contains a large number of cache tags.

Affected installations

This change affects all TYPO3 installations that have $GLOBALS['TYPO3_CONF_VARS']['FE']['debug'] enabled and misusing the X-TYPO3-Cache-Tags header for anything else then debugging. If you have a large number of cache tags, the header is now split into multiple lines to avoid exceeding the maximum header size limit imposed by some web servers. As this header is for debugging purposes only, this does not effect any production environments.