Slack avatar image is not loaded

Georg Ringer reported an issue

because of security headers the slack avatar is not loaded but error image is shown from browser

Reported URL:https://my.typo3.org/index.php?id=23

User Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36