Meaning, the real, free market exchange rate, not the official government capital control exchange rate.

Most currencies are free floating so it is the same, but the really bad ones are not (Turkey, Argentina, etc)

Blue market is the rate you get on the street (USD buys 10-40% more), official is what you get from a bank.

By comparing what each currency sells for in BTC, you can compare free market rates, fiat/fiat, instead of looking at forex. I just wondered if there was an automated tool that did this.