Function trace_dependency 

pub fn trace_dependency(
    graph: &ModuleGraph,
    root: &Path,
    package_name: &str,
    script_used_packages: &FxHashSet<String>,
) -> DependencyTrace

Trace where a dependency is used.

script_used_packages carries the package names recorded as binary invocations in package.json scripts (build: microbundle ...) and CI configs (.github/workflows/*.yml, .gitlab-ci.yml). The same set the unused-deps detector consults; passing it in lets the trace output match the detector’s view of “used” instead of reporting is_used=false for tools invoked only through scripts.