Sian,

Unfortunately there isn't (and probably never will be) a 'comprehensive reference' As with much Open Source software, slightly different standards develop, and not every ABC program supports them all. Many Mac users will argue in favour of Barfly's implementation of the standard. PC users for different programs. I don't know Linux, but I imagine similar differences.

Don't get me wrong, every ABC program will implement the vast majority of the standard, just not all of it. The link that treewind gives is for a new standard (ABC2) which further complicates things....

I don't know what tunes you posted, but at a guess the arguments were probably over the best way to show repeats or some such. Given the size of text(ABC) files compared to current computer/connectivity size, such things are a total non-issue.

Don't get discouraged, and post more tunes!

Ed