Express可以使用带有加密私钥的.pfx文件，而无需使用私钥密码

I have an express instance and an unencrypted pfx which contains my cert and an encrypted private key. When I load the pfx in express, I do not need to provide any sort of password, and it works. How is the node.js instance getting access to the private key? Isnt access to the unencrypted private key needed for https to work?I have an express instance and an unencrypted p