Are you going to take the exam? You can generate an SSL certificate that chrome doesn't trust and deploy it on the server to see the effect. For example, a self-signed SSL certificate can also apply for a cnnic certificate, because Google declares that it does not trust cnnic's SSL certificate. If you want to use a globally trusted SSL certificate, then the domestic CA Wotong SSL certificate is very good. The keyword is a free SSL certificate, which also supports all browsers. Testing is very convenient.