Kind of. It's only the traffic management part, i.e. the external load balancer. It seems to be a mix of a managed Istio Pilot plus a bunch of stuff from GCLB:

Kind of. It's only the traffic management part, i.e. the external load balancer. It seems to be a mix of a managed Istio Pilot plus a bunch of stuff from GCLB: anycast, backend subsetting (Envoy does not do the health checking), etc. TD just tells each client which servers to talk to. It doesn't forward traffic. And it doesn't seem to be responsible for injecting the sidecars in clients.