I'm about to rant about an existing Lilyond default. Really I want to suggest a change for the developers, but I'm not sure where or how to do that. So I'll start with this rant, and I'll be happy to take any more productive steps if someone can suggest what they should be. Or, if this issue has been previosly debated, I'd be interested to have a link to that discussion.
Here goes... I've been using Lilypond for a few years, and only yesterday learned about the point-and-click feature in pdf output. In particular, I had no idea that by default Lilypond includes absolute pathnames to local source files on my system as metadata in the pdf output files. So when I uploaded a couple of files to IMSLP recently, that metadata was available for all to see. Having learned (from my son!) about this feature, I have now found it in the manual, and I now know how to disable it. And I have replaced the publicly available files with new ones that do not have the metadata--and are also half the size! This point-and-click seems like a useful feature for editing, *if* it's configured to work on your system. But it apparently is not usually set up that way by default, at least on most Linux systems. (I do appreciate the instructions in the manual for configuring it, and plan to do that.) But even if it is configured to work, it seems like a REALLY BAD IDEA to have this feature enabled *by default*. Or, if it is to be the default, it ought to be mentioned VERY PROMINENTLY, so anyone installing and using Lilypond will see it. As far as I could tell, it is not even mentioned in the Learning Manual. The reference manual does admonish users to disable the feature when producing pdf output for public distribution. But that warning is totally useless if a user does not happen to read that (rather obsure) section of the manual. -- David Zelinsky