Open-source wallets survive on donations and grants mostly. The rest sell out ads and PII (personal identifying information) to data brokers.
This is normal for most free crypto wallet devs and they cut in every successful trade done by their use on the DEX. Besides, another project that offers almost this exact service is BestChange. Have not to wonder how they are making their money while they are not an exchange.
I think BestChange has a revenue-sharing system in place where the actually exchange you go to has BestChange's referral code or something like that.
Otherwise, the devs can earn transaction fees besides the prices in blockchain, they can do the same way like exchange add a transaction costs more than the regular fees
Developers cannot do that to any coin they'd like because they'd have to modify every transaction coming out of that wallet to send a comission to them. That is a HUGE gaping security hole. It's basically restricted to their own tokens via economy/blockchain measures.
I think they are going to shut down their business verysoon, and last thing I heard they are in Kazakhstan court.
Where did you get that information from?