Yes it’s opensource. I just have to finish the GUI and ready to go.
On the core protocol of TumbleBit not much work is done these days, testing and bug fixing and everyone else is working on other things, except me, because I’m on HiddenWallet. When I give out the first version of HiddenWallet that’s when the work will get started, since I’ll probaby rewrite the upper layers of NTumbleBit.
Btw are you by any chance participated in this reddit conversation?:) https://redd.it/5wdckm