This seems to be an example with wrong usage of g_variant_get() contradicting its definition:

{
  const gchar *str;
  GVariant *value;

  value = g_variant_new ("&s", "hello world");
  str = g_variant_get ("&s", &str);
  g_print ("string is: %s\n", str);
  /* no need to free str */
}


..taken from the "Pointers" section of "GVariant Format Strings"