Editor

You may be looking for:
 * the default MediaWiki editor, which is seen when Javascript is disabled
 * the "core" Javascript editor, Manual:EditPage.php
 * Extension:WikiEditor, the 2010 wikitext editor
 * 2017 wikitext editor
 * VisualEditor, introduced in 2013
 * Extension:WikEd, generally run as a user script
 * Extension:CodeEditor, introduced in 2011