op-packages/luci-app-nginx/root/usr/share/rpcd/acl.d/luci-app-nginx.json

{
    "luci-app-nginx": {
        "description": "Grant UCI/init/file access of nginx to luci-app-nginx",
        "read": {
            "ubus": {
                "service": ["list"]
            },
            "uci": ["nginx"],
            "file": {
                "/etc/nginx/conf.d/*.locations": ["read"],
                "/usr/bin/curl": ["exec"]
            }
        },
        "write": {
            "uci": ["nginx"],
            "file": {
                "/etc/nginx/conf.d/*.locations": ["write"]
            }
        }
    }
}