+* Identifier: The default value is the unique string identifying this
+ file (in the example above it was 'Packages') also accessible as
+ Created-By. The difference is that using this property multiple files
+ can be subsumed under one identifier e.g. if you configure multiple
+ possible locations for the files (with Fallback-Of), but the front-end
+ doesn't need to handle files from the different locations differently.