Why should NPM library authors care about Tree Shaking

Flat files are an issue for webpack: https://github.com/webpack/webpack/issues/9337#issuecomment-507179765

Don't bundle your library: https://github.com/webpack/webpack/issues/9337#issuecomment-524966201

What is tree shaking https://blog.theodo.com/2021/04/library-tree-shaking/

How it works: https://webpack.js.org/guides/tree-shaking/