The purpose of this theme is that it can be used to start a new theme from, eeehh, well… scratch.
So the display itself is unstyled. Some much used files are present, so there is no need to remove or add the same files/templates/functions every time a new theme has to be developed.
Version 3.x – only available for Drupal 7 – is a HTML5-version of this theme.
But hey, this looks just like Stark?
Yes, but it is quite different. Stark adds no templates. In Scratch the most used ones (html, page, node, block) are overwritten. Also Stark has no template.php to start from, or basic CSS structure.
Scratch is empty but tries to provide enough (documentation for) configuration to get started quickly.
Other options
Most core CSS is left in place, in template.php and scratch.info an example is given how to remove or overwrite those CSS files. If you want to remove all CSS from core or loaded modules take a look at the Unset CSS module or the Mothership theme.
For a much more advanced approach, with support for SASS, Compass, and Singularity (and more) you could give Aurora a try.
When making this theme HTML5, I borrowed a lot from Boron. And new features I would like to add might have a lot of resemblance with the aforementioned Mothership theme, which approach I like.
Some code is added to template.php to make search and dates HTML5-complient. You could achieve the same with the HTML5 Tools module.
