code: def _manual_overrides(_cache_date=None):
      
      log = logging.getLogger('ciu')
      request = requests.get("https://raw.githubusercontent.com/brettcannon/"
                             "caniusepython3/master/caniusepython3/overrides.json")
      if request.status_code == 200:
          log.info("Overrides loaded from GitHub and cached")
          overrides = request.json()
      else:
          log.info("Overrides loaded from included package data and cached")
          raw_bytes = pkgutil.get_data(__name__, 'overrides.json')
          overrides = json.loads(raw_bytes.decode('utf-8'))
      return frozenset(map(packaging.utils.canonicalize_name, overrides.keys()))
docs: Read the overrides file.
  
      An attempt is made to read the file as it currently stands on GitHub, and
      then only if that fails is the included file used.