This repository demonstrates the issue that Storybook Docs does not generate the source code of an Svelte story correctly.
To reproduce the issue, execute the following commands.
npm install
npm run storybook
Now a browser opens with Storybook. Select the "Button" story, go to the docs page and expand the source code panel with the Show code button.
The source code panel shows this code
<Button primary slot_default="Button Label" event_click={undefined}/>
But the panel should show this code instead
<Button primary>Button Label</Button>