Extending this codebase

I was looking at this codebase and encountered this bit:
https://github.com/bigscience-workshop/data-preparation/tree/main/sourcing/code_dataset#code-dataset-sourcing

```
The query to create the dataset can be found in query.sql. After creation the dataset was preprocessed with processing.py. Note that there is a bug in the script that filters only for GPL licenses instead of filtering them out. There are instructions to remove the bug but it is left there for reproducibility.
```
This leads me to believe that the code here is meant to be used and investigated "as is" and without modification.
Is this repo primarily meant for reproducibility?

If i wanted to improve and extend it for an independent Dataset building project, should I fork it or work from a branch?