Popup asking about user certificates?

I keep getting a popup asking:

Do you ultimately trust "CN=DigiCert Assured ID Root CA OU=www.digicert.com O=DigiCert Inc C=US" to correctly certify user certificates?

I have no idea where it’s coming from. Has anyone else seen this?

It is something local to your system.

You have fiddled in some setting - somewhere you have ticked a box and forgot where.

Likely in System Settings → Network → Settings

Perhaps SSL Preferences which also has a Defaults button you can use to revert any changes made.

Thanks, I didn’t even know that section of the settings existed. They all appear to be ticked at the moment, and I haven’t had a popup since I updated this morning, so not sure what happened there!