A link (or document link) is a placeholder within the text of a topic, pointing to a file on disk. The link is represented by a small version of the file’s Finder icon.
To make a link to a file:
If a topic contains a link, you can:
Double-click the link to open the file from the Finder.
Or, double-click the link while holding the ⌘ key to reveal the file in the Finder.