It seems to be similar to wearable called FOCI by Tinylogics. Has been there for at least 3yrs now. This may not be the first device or app focussing on breathing.
Nanoleq is currently crowdfunding for the Oxa breathing wearable, which it claims is a world first. The gadget can provide real-time data for health metrics such as your breathing depth and speed. You can use the accompanying app to practice breathing techniques which could improve your health and well-being over time.