For a web-noob, can you explain what node_modules contains and why we can exclude it? 🤔

@timhoffm:

I guess that meme is kind of: why you should exclude, though not why you can. That part is also a bit mysterious to me.

(I think it's basically where all of the javascript packages get stored so that you have something like virtual env for a given js project.) But then I'm also a web noob so if someone has a more substantive explanation please don't let mine stop yours

I think @timhoffm meant "why did we need it before, and why can we exclude it now?"

Maybe we didn't even need it before, but only nobody bothered to exclude it.

Rephrased question: Everything in the sources serves some purpose. Most of these things should be packaged. But apparently node_modules are not relevant for distribution. I'd like to roughly understand what it is and why it is not needed for distribution.

A rough explanation in 1-2 sentences is enough.

The node_modules directory was never needed before, and was never included, because sdists were created from a clean checkout. It would be created if you were working on the JS side of things and installed the linters and ponyfills we specified in packages.json. Excluding it is a convenience for anyone in that position who wants to test sdists, because that directory is somehow almost just as large as the rest of Matplotlib (yes, including test images).