A new @SanitizerInitiator@ is added and forwarded to @typo3/html-sanitizer@. This allows to get a full stack-trace when HTML nodes have been sanitized/modified and allows to debug the actual cause (initiator) much better. h2. How to test? * @composer req typo3/html-sanitizer:dev-main@ ** (or manually clone into @vendor/typo3/html-sanitizer@ directory from https://github.com/TYPO3/html-sanitizer) * apply patch from https://review.typo3.org/c/Packages/TYPO3.CMS/+/70484 (TYPO3 v10.4 currently) * have logging enabled as described in https://docs.typo3.org/c/typo3/cms-core/master/en-us/Changelog/9.5.x/Important-94484-IntroduceHTMLSanitizer.html#debugging-logging * have debugging enabled via TypoScript, like @config.debug = 1@ In case tags/attrs are modified, this will be shown in the log file, next to new @initiator@ stack-trace.