I understand from official Docs Anthos is built on Kubernetes/Istio/Knative but where does Anthos fits in Google cloud platform.
Can it act as configuration manager for application auto-deployment, provisioning etc ?
Does it provide support for language specific build on the fly?
with Anthos you can basically manage multiple Kubernetes clusters from multiple Clouds( Amazon, Google, Azure) and on-prem. It can help you mantaining a hybrid environment and moving in a predictable way or partially your infrastructure from on-prem to cloud .
You can use Anthos Config Management to create a common configuration for your clusters.You can use ClusterSelectors to apply configurations to subsets of clusters. Configuration can include Istio service mesh, pod security policies, or quota policies.
From security perspective, you can manage your policies using Anthos Policy Controller, enforcing PodSecurityPolicies, with the advantage of testing constraints before enforcing them