title: What is my google-signin-client_id
body: <p>My web site used to have a link to let users login with their Google accounts in Open ID 2.0. Since 20.4.2015, this is no longer working, so I am trying to migrate to Google Sign-In.</p>
  
  <p>This page:
  <a href="https://developers.google.com/identity/sign-in/web/sign-in#specify_your_apps_client_id" rel="noreferrer">https://developers.google.com/identity/sign-in/web/sign-in#specify_your_apps_client_id</a></p>
  
  <p>says: </p>
  
  <blockquote>
    <p>Specify the client ID you created for your app in the Google Developers Console with the google-signin-client_id meta element.</p>
  </blockquote>
  
  <p>I have no idea what my client ID is. In my Google Developers Console:
  <a href="https://console.developers.google.com/project" rel="noreferrer">https://console.developers.google.com/project</a></p>
  
  <p>there is only a single, very old application I created with GoogleApp, which is not related at all to the website I am talking about.  I tried using its project ID anyway, and got the following error after clicking the sign-in button:</p>
  
  <pre><code>401. That’s an error.
  
  Error: invalid_client
  
  The OAuth client was not found.
  Request Details
  
      fetch_basic_profile=true
      scope=email profile openid
      response_type=permission
      redirect_uri=storagerelay://http/localhost?id=auth684995
      ss_domain=http://localhost
      client_id=imitatorgwt.apps.googleusercontent.com
      openid.realm=
  
  That’s all we know.
  </code></pre>
  
  <p>What exactly should I write in the google-signin-client_id meta tag?</p>