I remember that I used to click an example in the doc and see the text
file in the browser window. Now I'm prompted with a window which asks me
which application I should use.
I don't know what's changed but I think that it's something introduced
in the "recent" browsers (???). If you try the attached html file,
you'll see that a .txt file is opened within the browser while a .ly
file needs an external application.
We've always used .ly files...
This behaviour is actually fine for me, because this allows me to set my
favorite lilypond editor and avoid the copy and paste.
But maybe the Learning Manual should be rephrased in this section?
"If you click on a picture in the HTML version of this manual, you will
see the exact LilyPond input that was used to generate that image. Try
it on this image: "
"By cutting and pasting everything in the “ly snippet” section, you have
a starting template for experiments. To see exactly the same output
(line-width and all), copy everything from “Start cut-&-pastable
section” to the bottom of the file. "