About the lock icon
When you see a lock icon to the left of web site address, you know that you are visiting a secure website. This means you can safely enter confidential information here, because QtWeb has verified the website's ownership with a certificate and will encrypt any information you enter.
To view the contents of this website's certificate, click the lock icon.
If QtWeb has verified SSL certificate successfully, webpage URL is displayed on the light-green background. If there some SSL errors detected while certificate verification - QtWeb displays these errors and draws URL on the pink background, advising you that this certificate is not reliable (unverified by trusted authorities). Errors could happen in different scenarios, for example certificate is expired or certificate is self-generated (for development or testing purposes) but not certified, etc... SSL errors do not mean that connection is not secure! Https connection is 100% secure, however the host you are trying to connect to has not been registered or verified with trusted organizations.