The WS-EventDescriptions spec does not specify/recommend/encourage 
any specific file extension for event descriptions. Without an agreed 
upon extension, the event descriptions could potentially be specified in 
an .xml file. That means when trying to find the definition for a QName 
of an event type, one would have to potentially go through all the .xml 
files (which can be very large) within one's scope of resolution to see 
which one contains event descriptions. This is a potential problem for 
the SCA Assembly spec [2] and other specifications/applications that may 
want to reuse event descriptions. A standard extension, for example, 
.evd, would also help wrt associating event description files with tools 
that work with those files. For example, appropriate editors.

2) The WS-EventDescriptions spec recommends the use of 
WS-MetadataExchange and WS-Policy for retrieving event description. This 
might be appropriate for applications that already use those 
specifications, but is an unnecessary burden for applications and 
specifications (such as SCA) that do not require Mex or WS-Policy. An 
additional mechanism similar to something like 
schemaLocation/wsdlLocation would be more useful, simpler, and would 
promote reuse of WS-EventDescriptions.