You must be looking in the wrong place, or for the wrong thing. The GP editor uses only the GP Name, while the documentation and the registry refer to GP unique name. This is what the documentation says:
Windows information and settings
Group Policy (ADMX) info
GP unique name: OverrideSecurityRestrictionsOnInsecureOrigin
GP name: Control where security restrictions on insecure origins apply
GP path (Mandatory): Administrative Templates/Microsoft Edge/
GP path (Recommended): N/A
GP ADMX file name: MSEdge.admx
and this is what I see in the GP editor: