I just can't find a way to delete the Self-Signed Root CA from Keychain under System.
When I open KeyChain I select System under System Keychains. Then I click on the File in menu and then click on Unlock Keychain "System"...
After this I was expecting to be able to delete a certificate. But when I select a certificate I can only see greyed out Delete option in the Edit in the menu.
I tried to disable SIP (which was successful) but it did not help me clear From Keychain file (SystemRootKeychain) which is:
I disabled SIP in Recovery mode with command: