If I have understood the purpose of this page (https://www.cmegroup.com/market-data/licensed-quote-vendors/) from the CME correctly, it lists all the third parties that are licenced to distribute CME real time data.

So you can see in the list the likes of CQG, CTS Cunningham, Bloomberg, Thomson, DTN, Bar Chart and Trade Station.

But where are the likes of Rithmic, Trading Technologies, Open E-cry/Gain, Interactive Brokers and E-signal etc?

Who are they getting their data from, or is it a name on the list that is not obvious compared to the brand they market the data under?

They source the data from a licensed vendor and tend to repackage the data, or re-process it on route (e.g., filter tick data, or summarize the data or re-quote prices). However sometimes you are provided the data un-edited, see the specific vendor for details.

Essentially for non licensed parties its cheaper to source the data from an existing licensee than to pay to become licensed. They can agree a cheaper price form the licensee by committing to provide X number of new subscribers annually and when they sell data feeds to their clients they add a premium / discount to that fee , which they make a commission on / with a discount they get more general business from. (e.g., the earn a commission on the feed from what you pay / they earn more business).

sands 

They source the data from a licensed vendor and tend to repackage the data, or re-process it on route (e.g., filter tick data, or summarize the data or re-quote prices). However sometimes you are provided the data un-edited, see the specific vendor for details. Essentially for non licensed parties its cheaper to source the data from an existing licensee than to pay to become licensed. They can agree a cheaper price form the licensee by committing to provide X number of new subscribers annually and when they sell data feeds to their clients they add a premium / discount to that fee , which they make a commission on / with a discount they get more general business from. (e.g., the earn a commission on the feed from what you pay / they earn more business).

So, naturalists observe a flea
Hath smaller fleas that on him prey
And these have smaller still to bite 'em;
And so proceed ad infinitum.
—Jonathan Swift

... so run the markets...