Required?: YES (Inside a link)
This is the name of the icon to be displayed for this link. The actual required size and rendering location of this icon depends on the link type, so check there for details.
If the locale:key is provided, as well as a basic path inside the element, then the locale:key value is used and the element text ignored. This key is located in the current locale's bundle as per bundle action so the images can be localized.