Where are the classic theme source .scss files for PrestaShop 8.x.x

[seakrebel]

I wanted to adjust the theme.scss of classic theme from PrestaShop 8.x.x to have a child theme based on it. But I can't find the source files anywhere.

I was able to find them in the 1.7.8.x branch, and while I thought the classic theme was 1:1 same on the front-end, I found differences and bugs when I compiled the original theme.scss from 1.7.8.x and used it for the v8.1.5.

So it has to be another source but it is not available for public in the 8.x.x or develop branch on github. Does anyone have more information on this?