> I think a store item doesn't know where it comes from, so you can only
> find its runtime references.

That's a good point. I missed that.

> If you have a package foo, you can find its build-time dependencies
> with guix graph:
>
> guix graph foo

Indeed, this is what I want but for a modified version of a package
defined in a file. I realized I could do it with

guix graph -e '(load "/path/to/file.scm")'

However, it might be nicer to have something like

guix graph -f /path/to/file.scm

similar to

guix build -f /path/to/file.scm

> There's even a script that was shared here to show the path between
> two nodes of a guix graph, but I can't find it anymore.

Yes, I remember such a script too. It would be very useful to have. But,
even I am unable to find it. If someone knows where to find that script,
please share a link.