If I use coinjoin like JoinMarket, does JoinMarket keep track of transactions or logs some other information regarding my transactions? Are the smart contracts public somewhere?
In a JoinMarket coinjoin, there are makers (who provide liquidity) and takers (who buy liquidity from them). These coinjoin transactions are all public on the blockchain, with a distinct footprint. Takers trust no one in JoinMarket. Makers leave a log of the movement of funds with the taker who pays for their liquidity.