I don't think it is generally known, but a line beginning with a '#' is a comment in wml. They are html comments - they do not even show up in the .html file.
This is probably the best way to leave notes for translators. For example, translators probably will not want to translate the files in releases/potato/. With a comment telling the status of a file they can judge for themselve whether it is worth their effort or not. Jay Treacy