The main file of a component is by default expected to have an `.html` or `.svelte` extension. This can be configured by initializing the plugin with `svelteCombiner({ extensions: ['.something', '.another'] })`. These should typically be set to the same `extensions` as are passed to the main `svelte` plugin.
The javascript portion of the component should have the same path and filename but with a `.js` extension. The stylesheet portion of the component should have the same path and filename but with a `.css` extension.