I don't have an example file on hand, but they would be useful for documenting non-explicit dependencies between packages. e.g. Kendo UI and the corresponding theme packages[1] - neither NPM package depends on the other, but if there's a comment then when seeing a change to one, the developer or a reviewer should know to double-check the other.

[1] https://docs.telerik.com/kendo-ui/styles-and-layout/sass-ver...