From Opus

You can export the text and editing history of a particular page or set of pages wrapped in some XML. This can be imported into another wiki using MediaWiki via the Special:Import page.

To export pages, enter the titles in the text box below, one title per line, and select whether you want the current version as well as all old versions, with the page history lines, or just the current version with the info about the last edit.

In the latter case you can also use a link, e.g. Special:Export/Welcome for the page Welcome.