Differences beween Categories and sub-Categories?

[Moin]

Usually, when you look at all topics from a category, you also see the topics in the subcategories. For example, when you look at #announcements, you also see the topics in #announcements:blog. Of course, you can use the subcategory filter and select “no subcategories” to exclude them or change the category settings so that subcategories are hidden by default. But in general, a parent category can also work to group several subcategories, like for example Documentation does.