storybook/code/lib/builder-manager/README.md

Manager-Builder

Do not use this package unless you know what you are doing. Storybook uses this package internally to create the manager side of storybook.

This package uses esbuild to bundle the manager-side of addons, and prepare it for modern ESM supporting browsers.

Each addon is bundled into a separate file, and the manager is responsible for loading them. In addition, if manager.* exists, it's also bundled, and loaded.

Additionally this package also will add the manager ui via the @storybook/ui package, which is already build by esbuild in our build process before publishing.