OK, but either way, they get the data from Yahoo. Its not their own. I don't know if Yahoo supports futures and they definitely do not have intraday historical data
For delayed, you can register for free at quote.com and then select them as the quote source in QT. Symbols such as:
NQ03U
ES03U
but there are no sources for backfilling that data. <edit> for free. All the backfill sources for futures are paid subscription, or brokerage (CyberTrader)
As for getting long period charts, you would need a source that supports continuous contract symbols, which are not supported by our historical chart providers as far as I know