MediaWiki's VisualEditor one of the two editors which are available for this wiki. It shows you what the edited page will look like while you're still editing it and you do not need to use Wiki markup code (WYSIWYG).
In case you prefer the previous source editor, you can always switch back: 1. There are two edit tabs/links on each wiki page, 2. you can set it permanently in your wiki edit settings.
For some more info on this alternative editor see
- Wikipedia's internal help about VisualEditor,
- Wikipedia article about VisualEditor or
- MediaWiki's software project page (MediaWiki is the software which runs this wiki).
(this page is linked from automatic wiki page edit tags which used the new VisualEditor)