It looks like abandoned project now as there is no website and as you pointed out no availability of wallet. I also tried to access their Github account but it has gone already. Someone tried to check the market's response but there is none. We don't see any comment which to encourage the development and it has done.
No, its not abandoned ... still running and working.
https://lightning-cash.comor
https://bitcointalk.org/index.php?topic=5117428.msg50040034#msg50040034