It combines posts from various multisite subsites into a fixed layout that you cannot further customize, except that you can limit the display to a specific category. By default, it displays the posts from your subsite—that is, your blog. Use the Post Archive block to organize your previously published posts by year, month, week, or day. In addition to a standard Archive Block, you can search for posts and filter them by various categories. This is useful for readers who are browsing your older content.