The Register of Scottish Tartans classifies it as a clan/family tartan, even if it is often regarded a universal or general tartan. It is rather special, the pattern being asymmetric.
Scottish Tartans Society notes (Source The Register of Scottish Tartans): "The pattern books of the old firm of weavers, Wilson's of Bannockburn, provide the first record of this sett which was not published until 1886 when James Grant included it in, 'The Tartans of the Clans of Scotland'. The pattern is unusual in that the half sett is not reversed to create a symmetrical square. Instead the full sett is simply repeated from right to left across the cloth. There is no reliable explanation of why the Hunting Stewart should be regarded as a 'General' tartan".
Nevertheless it is one of the most popular tartans, at all. It should also be the one Queen Victoria found to be the most beautiful of all tartans, by the way.
The kilt is a cheap casual kilt from no longer existing Tartan-Wear Direct in Glasdow. On the big picture, bottom left, you can see that the arrangement of the vertical stripes is far from being perfect: Yellow-red-yellow; red-yellow-red; red-yellow-red; where they should all have been red-yellow-red or yellow-red-yellow.
I have sold the kilt.