Where does error message come from?

[Steve]

While trying to get the mixer working from the Vol control plugin, I got the following error message:-

Error, you need to install a application to configure the sound (pavucontol, alsamixer, ...)

Where does this come from, or how do I find which package generated it, as it has a grammar and a spelling error in it which I would like to correct/report.

-- 
Steve <yorvik.ubunto at googlemail.com>