How to delete a root CA (Certificate Authority) certificate from Mozilla Firefox 125? I don't know this root CA and don't want to trust any Websites that uses this root CA.

If you want to delete a root CA certificate from Mozilla Firefox 125, you can export it to a file first, then follow this tutorial.

1. Open the Certificate Manager as shown in the last tutorial.

2. Click "Authorities" tab. You see the list of root CA certificates showing up.

3. Scroll down in the list and click "Certainly Root R1" to select it.

4. Click "Delete or Distrust..." button. You see a warning message showing up.

You have requested to delete these CA certificate. 
For built-in certicates all trust will be removed,
which has the same effect. Are you sure you want 
to delete or distrust. 

If you delete or distrust a certificate authority 
(CA) certificate, this application will no longer 
trust any certificates issued by that CA.

5. Click "OK" button to finish deleting the root CA certificate.

⇒ Import Root CA Certificate into Mozilla Firefox 125

⇐ Export Root CA Certificate from Mozilla Firefox 125

⇑ Using Certificates in Mozilla Firefox 125

⇑⇑ Firefox Certificates Tutorials