[question] How to validate sha256sum change?

[Koschi13]

Hi,

I'm quite new to the nix Project and everywhere I'm told to "just replace" the sha256sum with whatever the error shows.
Most of the time I can figure out where this hash is coming from and I am able to verify this.

However, with this flake I'm a bit lost on what to check.
Can someone please point me to the code which is responsible for the check or even better, can someone explain me what I need to validate?

Thanks in advance