Drei Bounds why use atan?

As I had some problem while using Bounds component, I looked up its code from github.
drei/Bounds.tsx at master · pmndrs/drei (github.com)
But I can’t understand why it ueses Math.atan instead of Math.tan.

Could anyone know its reason?

no reason, the code was scraped off various places on the internet. if you understand what’s going on and you have a repro make a pr and it can get fixed. i would be happy if someone looks over it because bounds does seem to have some degree of freedom it shouldn’t have when zooming to fit.