src/Extensions/ContentReviewCMSExtension.php
protected function getSchemaRequested()
    {
        $parts = $this->owner->getRequest()->getHeader(LeftAndMain::SCHEMA_HEADER);
        return !empty($parts);
    }
protected function getSchemaRequested()
    {
        $parts = $this->owner->getRequest()->getHeader(LeftAndMain::SCHEMA_HEADER);
        return !empty($parts);
    }
Check if the current request has a X-Formschema-Request header set.
Used by conditional logic that responds to validation results

@todo Remove duplication. See https://github.com/silverstripe/silverstripe-admin/issues/240

@return bool