I've seen the posts on your forum from back in 2009, but no list has yet been provided. As the other posts referred to the specific variable they wanted the definition for, and that part was addressed, they have been marked as answered, but the underlying reason for those posts has not been addressed. In PeterJ's post, he asked for why you don't offer a list, but the question was not addressed.
So, I solely request a list of variable/symbol names (such as %%year%% and %%itemname%%) and their definition and/or value source so that your customers can reference this information without contacting your support for assistance, and so that they can refer to it to discover potentially useful symbols.