Physical Storage of InMemory Cache of Apollo Client

According to Apollo Client docs, the InMemory cache is used in the apollo client cache as instantiated in the below code

import { InMemoryCache, ApolloClient } from '@apollo/client';

const client = new ApolloClient({
  // ...other arguments...
  cache: new InMemoryCache(options)
});

Reference: https://www.apollographql.com/docs/react/caching/cache-configuration/

1. Where is this in-memory storage physically created? Is it in sessionStorage or localStorage or indexed db or front-end servers?
2. What is the lifecycle of stored data inside this cache?is it deleted on closure of browser session like session cookies or tab closure like session storage?