How is the classic file hash created?

### problem description

Hi,
Great app, but how is the *classic info* **hash** created from the the file?

---

<img width="1142" height="504" alt="Image" src="https://github.com/user-attachments/assets/63310a38-178e-4ab6-8c01-c71d5f3fd2b9" />

### your instance configuration

```shell
n/a
```