Pixi.js + gsap? Blurry background animation on mouse position change. How do they do it?

I found this cool looking website and I would like to understand how they’ve done this effect: https://monopo.london/

The background is a blurry, multiple color mesh gradient or something like that. When you move the mouse, the gradient points changes position but in a very interesting way.
As far as I can tell the website is using gsap and pixi.js . I looked into the pixi.js docs but cound’nt find any help there.

Can someone help me understand how they did this effect? I would really appreciate any help! Thanks 🙂