MWB is a tool for Microsoft Windows 2000 (and newer) that helps editing MediaWiki type wiki pages. The tool can build a list of pages and assist in doing edits to these pages. Changes to pages can be specified by defining hierarchical search and replace rules.
MWB loads a page from the list, applies the changes and displays the result in a window that contains the same diff or (pre)-view as provided by a normal webbrowser. The user has the ability to do additional edits in a text editor window. Previewing and diffing display is provided by the MediaWiki server generated html output.
MWB is not a bot, because its normal use is intended for interactive edits under direct user control. Users are expected to carefully review each diff before they save an edit—the same as when using a simple webbrowser.
MWB can assist in doing tedious repetitive/complicated editor-work, like exchanging one template call with another or replacing names of template parameters. MWB has some limited wikitext parsing capabilites.
More information on MWiki-Browser is available at meta:MWiki-Browser.