[jusob]

There are 3 ways to intercept HTTPS transparently (without a big SSL warning):

1. Put the intercepting SSL cert root in your local trusted store. This is how it is done in enterprise. The certificate is typically pushed through an MDM installed on each computer/phone. This is also how Fiddler works. This requires administrative access to your device to push the certificate root as trusted.

2. Create a rogue certificate from an existing trusted certificate registrar. This is why is a risk with nations like China where "private" SSL registars mybe forced to issue certificates for Google or other sites to the government. This was supposed to be fixed with Certificate pinning (now deprecated), and now with certificate transparency log. But the later has a few weaknesses in practice: - rarely set as enforced by the websites, or set at at all - requires each company to monitor the transparency log and get rogue certificate canceled. I don't know of any company which actually does that.

3. Interception inside the browser through an extension or plugin, or plain process hijack. Since the browser does the HTTPS encryption/decryption, an application taht runs inside the browser with the right access can see all decrypted traffic.