lilypond.org Productions page

[Federico Bruni]

Hello

I was about to send a patch to add a website in the Productions page 
(sheets are CC licensed, subscription required):
https://www.baroquemusic.it/

Then I realized that 3 out of 4 projects listed under "Published sheet 
music" section are discontinued.
Should we just delete them?
http://lilypond.org/website/productions.html

Which are the requirements (if any) to be listed on that page? Should 
we link only projects following Free Software principles?

If you know of any other project which may be listed there please let 
me know.

Thanks
Federico