I imagine one could be part-tester and part-writer. Both the tester and the documentation writer need to understand how the application works (at least from use

I imagine one could be part-tester and part-writer. Both the tester and the documentation writer need to understand how the application works (at least from user perspective). The work for testers comes in waves; they could work on documentation between the waves. It could even make sense to highlight in user documentation, which parts are already done and tested, and which are still missing. But these days many companies don't even have testers as a separate position, so... dunno, who else is left, besides managers and developers? Perhaps the janitors could take some extra reponsibility.