Root CA used in client.badssl.com

[Truth-]

Hi,

I'm unable to find the root CA used to generate the client certificates https://badssl.com/download/

My application gets the following error when trying to do a GET request on https://client.badssl.com/:
[PocoHTTP] [ERROR] LogInvalidKeyHandler.h:25 Unable to verify certificate: unable to get local issuer certificate

I believe this is due to it openssl not being able to verify the trust chain.

So is the root CA available for download somewhere so that i can add it to app.

Thanks in advance