Once the developer makes her selections and hits submit, the system looks at the submitted configuration and if it’s not an external resource, it writes a file to the filesystem of the Drupal site.
Now that you’ve created your library of Snippets, you can then make use of them on your content. From either your Content Type, Paragraph, or other Content Entity – simply create a new reference field. Choose “Other”, then on the next page scroll through the entity type list till you get to the configuration section and select JSnippet. Your content creators will then have access to the Snippets when creating content.
Because these snippets are configuration entities, they can be captured and exported with the site’s configuration. This allows them to be versioned and deployed through your standard deployment process. When the deployed configuration is integrated, the library is built up and any JS or CSS is written to the file system.