How do you use yalc and npm/yarn in the same package?

[DanKaplanSES]

I'd like to see the answer to this in the README.md. It says:

• yalc can be used with projects where yarn or npm package managers are used for managing package.json dependencies.

I'd like elaboration on this because I can think of multiple ways to interpret it. How do yalc and yarn/npm cohabit the same package without stepping on each other's toes?