Can someone who understands this, explain the relationship bw the English names (Light, Flex, whatever), and how they relate to the single digit fare codes? Are certain codes only related to certain English descriptions (Light, for example), or can the same code be under different English names? I would be quite grateful to be filled in.

I am more interested in how the biz class ones work, but I suppose the logic is similar to economy (thus this thread)? Or are there differences bw biz and economy too?

I recall a thread some months back, with an answer from brunos​, and it highlighted to me how I don't think I actually understand how CX differentiates.