Problem with unused library functions

My name is Hernan; with a group of colleagues we are conducting a research about unused code present in dependencies of JavaScript projects. We call this functions, UFF (Unused foreign functions). We found that in most projects there exist a great amount of UFF that are being included in the final bundle.

In the case of underscore.string (v 3.3.4) our tools detected approximately 6 unused function in dependencies. Removing those functions, the size of underscore.string bundled could be reduced at least 2% (All tests passed). I’m attaching the reduced version of your project.
[underscore.string(optimized).txt](https://github.com/epeli/underscore.string/files/671166/underscore.string.optimized.txt)

I’ll be very grateful if you can answer me the following questions:
-Did you were aware of the existence of these unused functions in your projects?
-Do you think that this is a problem?
-Do you think that can be useful a tool for deal with this kind of problem?

Thanks in advance.

Cheers,