Breaking: #86492 - Removed stdWrap support for config.additionalHeaders

See Issue #86492

Description

The feature to use stdWrap for config.additionalHeaders has been removed due to an incompatibility with page caching.

Impact

stdWrap cannot be used anymore to manipulate additional headers set via TypoScript.

Affected Installations

Any TYPO3 instance that uses this feature, which has been introduced with version 9.0.

Migration

For the time being there will be no TypoScript based solution for dynamic HTTP headers.

Consider implementing a PSR-15 middleware to add advanced logic for additional frontend response headers.