In the AI era, it is especially more imperative for APIs to be documented than ever before.
For a human, when it comes to reading source code vs reading documentation, the time difference is not too big.
However! There is a HUGE time difference between a human reading source OR documentation and an AI having proper docs to as a roadmap to quick proper code instead of unnecessarily complex workarounds, usage of a less ideal API over a better one, completely new unnecessary invented code, or hallucinations.
I beg of you, please, never release an API without documentation in the new era. Not having documentation makes AI usage a lot less efficient than it is comparing to projects with good documentation.
Documentation serves as not only a guide, but a compass that ensure AI will expand its own context in the best way possible.
Please. 
One example is expressApp is not documented:
It may seem simple to some of you, but if it is difficult for a human to search for APIs, it is also more difficult for AIs than it can be.