What is dist files in js repositories? [duplicate]

This question already has an answer here:

• What is the role of src and dist folders? 1 answer

I read https://bower.io/blog/2017/how-to-migrate-away-from-bower/ and due to lack of experience in JS world I don't understand following sentence:

c) Module authors currently suffer from supporting two module ecosystems (and dist files in repositories).

While I know about two ways of packaging JS projects I am not familiar with "dist" files.

I saw them inside Git repositories of many projects (like jQuery). It is dev + minified versions of library + different extra resources.

I used files from this directory as quick way to extract dependencies into my project though I didn't realize that this is especially established convention.

What is dist files in js repositories?

Why we see them in WEB related libraries / frameworks?

Is it semi-official standard?

What should I do to provide "proper" dist files if I become WEB OSS library developer?

Is it discontinued practice and what is an alternative?