Each style directory becomes an entrypoint of Webpack build process. (e.g. The files within bs5 would be transpiled summernote-bs5.js and summernote-bs5.css.)

If you put a html file named summernote-<style>.html, it would be good for development and debugging processes. By running yarn dev, you can test styles manually on web browsers via those files.

Also, please don't forget to add summernote-<style>.json which contains additional information will be used in building processes.