Also not mentioned, they’re not unique across time: six base-36 characters is only 2 billion possibilities, wouldn’t surprise me if the largest GDS would blow through the entire space within a year. <https://support.travelport.com/webhelp/smartpointcloud/Conte...> suggests they get purged after a week, and recycled.

I wonder what fraction of the space is occupied at any given time.

Interesting post. One detail I don’t see is how the ROE info actually tells you what currency to convert to. I see the exchange rate calculation but how do you know what the final units are?