Difference between GCP HTTPS LoadBalancer access logs and istio logs

I have several GKE clusters to which I have manually deployed istio (manually, as opposed to the managed istio offered by Google Cloud in GKE)

I recently received an email from Google notifying me that

Google Cloud Platform will change the default behavior of HTTP(S) Load Balancing such that logging is no longer enabled by default.

Since my GKE clusters create HTTPS LBs for istio-ingressgateway resources, is whether there is any kind of logging pertaining to HTTPS LBs that I cannot see in istio logs?