I think it could potentially be us too, though not sure. It was a very flexible product and we had a variety of use-cases. :)

We also had a lock screen app that you needed to play a tune on an instrument in order to unlock the screen. This too died because of Google maintenance burden (it had 500k downloads IIRC). Here's what I could find about that one: https://music-lock.en.softonic.com/android