This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
Internet Explorer and HTML tag abbr¶
Before IE7, Internet Explorer did not support HTML tag abbr. If a content element containing this tag is edited with htmlArea RTE in IE6, the tag may be broken. Therefore, abbr tags are transformed to acronym tags if IE6 is used.