Added link

app/src/main/java/eu/faircode/email/FragmentSetup.java

@@ -312,6 +312,7 @@ public class FragmentSetup extends FragmentBase {
                                         .putExtra("askAccount", provider.oauth.askAccount)
                                         .putExtra("askTenant", provider.oauth.askTenant())
                                         .putExtra("pop", provider.pop != null));
+                        // https://developers.google.com/identity/branding-guidelines
                         int resid = ("gmail".equals(provider.id)
                                 ? R.drawable.google_signin
                                 : res.getIdentifier("provider_" + provider.id, "drawable", pkg));