Responsive composition resize

[nicolo.maragno]

Hello world,
is it possible to resize a composition with an expression in AfterEffects?
This could sound as an old thread but all existing related posts are almost 10 years old and now it's 2020 so maybe something has changed and there's a solution.
I'm asking this because I've recently watched a Tutorial on YT which shows how to make a responsive design scene in AfterEffects.
This is the Tutorial:

https://www.youtube.com/watch?v=CEXFIPPAR4w&t=38s

At 0.38 seconds there's an interesting animation where the guy resize the composition simply dragging left/right/up/down a scale handle of a null object.
You can also see what I mean from this Gif

https://imgur.com/IAoRLdP

I'm not sure if it's just a fake representation or if it's a real thing but, if it's a real thing, it would be interesting to understand how to do that, maybe with a script?
I'd love to know if anybody out there could possibly know the answer to this arcane =)

Thanks everybody