The certificate is used by the proxy to intercept https requests. Without this option we could only handle http requests, which wouldn't work, because GitHub's cache api runs on https.

Got it, thanks for the clarification. I was misunderstanding how a proxy works when a client requests an HTTPS connection. So, it looks like there is no way to pass the unencrypted traffic to the proxy before it intercepts and establishes the HTTPS connection.

Anyway, maybe not strictly related, but I still have some doubt about the variable NODE_EXTRA_CA_CERTS in the doc:

Isn't the runner using C# and not Node.js, why we should add a that variable? I guess because the actions cache is using Typescript: https://github.com/actions/cache , right?

Thanks