Within a Sketch file there are often pages and arttboards with outdated designs or wireframes only for testing purposes. Now when creating document styles, there should be a way to exclude these pages or artboards because all the old and actually unused styles and colors clutter the style inventory up to unusable.
I tried the feature on a project I'm working on that has just a few colors and text styles but I ended up with dozends of entries on my styles page, most of them from the archived artboards of the early test stage.
To exclude a page or an artboard from the style inventory some special characters in the name could be used ie. "-styles" or simply "-cs".
However thanks for making Craft anyway, I use it a lot. 8-)