InDesign inserts a marker in text for items such as index entries, XML tags, and hyperlink text and anchors. These markers have no width and they don’t affect composition of text. However, you can select these markers and cut, copy, or delete them. InDesign uses the location of the marker to produce an accurate bookmark or page reference in table of contents, index, and exported PDF files.
You can view all markers at once, or view hyperlink or tagged text markers only. You can also view markers in Story Editor, where they are larger and easier to identify.