Why are is some data available to download and others not available to download?

 

When I go to the data explorer and look for the EURUSD data, the "Add to cart" button is avilable on the page however when I find the QQQ data, the "Add to cart" button is not available. Does this mean there is no way to make QQQ data available to my the backtests I'm running locally?

 

Thanks!

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