There is no such file in Alora Theme.
You can take a look at our demo site’s page source.
In your website page source, I can see the following stylesheet link.
<link rel='stylesheet' id='alora-dynamic-css-css' href='http://reimfelden.de/wp-content/uploads/alora.css' type='text/css' media='all' />
Check with your developer, whether he has added this link in header.php or via any custom function.
Or maybe it was left over by a plugin you previously installed.
All custom css in Alora theme is printed in HTML head by
<?php echo $smof_data['custom_css']; ?> in header.php, custom css are not printed as an uploaded stylesheet in uploads folder.
In your page source, I am not seeing the custom css code that I provided.