Wow, thanks for such a rapid response. Yes, I am sure that I installed it from the script, about 6 months ago, I guess. So I was not surprised to see that neither Synaptic of Software Manager were aware of it. And no, I did not reboot: meaning that I did not pay sufficiently close attention to the messages produced by the script (in my defence I have to say that messages of this nature, from most software installations, do not have any meaning to me: a bit like talking to me in Finnish language with a noticeable Hungarian accent (which I would not notice)).