From T247365:
<file name="includes/GlobalBlockingHooks.php">
<error line="187" severity="warning" message="Calling method \OutputPage::addHTML() in \GlobalBlockingHooks::onSpecialContributionsBeforeMainOutput that outputs using tainted argument $[arg #1]. (Caused by: Builtin-\OutputPage::addHTML) (Caused by: Builtin-\Html::rawElement; Builtin-\Html::rawElement; ../../includes/Html.php +210; Builtin-\Html::rawElement; Builtin-\Html::rawElement; Builtin-\Message::parseAsBlock; Builtin-\Html::rawElement; Builtin-\Html::rawElement; ../../includes/Html.php +210; Builtin-\Html::rawElement; Builtin-\Html::rawElement; includes/GlobalBlockingHooks.php +184)" source="SecurityCheck-XSS"/>
</file>It's as long as useless.