#Cashu is one #ecash implementation. #Fedimint (what i work on part time), is a different implementation. Cashu is much more mature in its UI/UX so you're more likely to have encountered it. Especially here on nostr.
Discussion
oh how to use fedimint?
Check out https://www.fedi.xyz/builders
They're a company running fedimint things and help on the protocol. Otherwise, it's really just technical people experimenting and iterating on this new and emerging protocol/tech.
thanks!