I am not familiar with the precise definition of the GEDCOM format but I think this is partly a matter of terminology. In RM a fact definition contains up to three basic attributes: Date, Place, Description. (All facts can have the Note, Source, and Sort Date fields). I have examined GEDCOMs exported by Legacy and FTM2012 and it seems that the Description is contained within the 1 EVEN label. According to an analysis on The Complete Genealogy Reporter website http://www.tcgr.bufton.org/tcgpcomp.htm
this is a non-standard use of the EVEN tag. Incidentally that web page is well worth reading if you intend to move data between different genalogy programs.