At the side of a writing or between paragraphs of text, you can place an area to provide additional information, a summary etc., which is called a "sidebar" in the publishing "scene", but in this service it has already become known as a sidebar. It is possible that this may be confused with a slightly later feature, which has been provisionally named "sideshow" and which is basically a sidebar at the side of the front page of a work, where basically anything can be placed (statistics, advertisements etc.). Here are a few available sidebar border style adjustments to make it stand out from the rest of the text.