When testing with FF browser, I discovered that the behavior of FF changed with version 57 regarding a URL attribute in combination with the rel attribute inside an HTML page. The code looks like this: <a href="https://123.456.789.100:9443/context/root/value" aria-label="see this link" target="_blank" rel="noreferrer"> The result is a link item on the web page that can be clicked and the corresponding URL is opened. Due to a requirement of the target web server there MUST be NO refferer information sent with this request or otherwise the URL will not be displayed. Therefore, the rel="noreferrer" attribute was added, which worked for all relevant browsers - so far. Starting with FF 57 and also tested with FF58, the rel attribute is not honored anymore and hence the link will not be displayed correctly. Is that a defect or did the behavior change by intention.