+1.
The objections to this fall into two forms:
1. We don't have prior art in the syndication space that proves this is needed.
2. This is someone else's problem, e.g. SOAP
I can see both those arguments, but when I re-visit and re-read this, the implementation is so falling-off-a-log obvious, like one small subroutine, that if you're doing cost/benefit math, the cost is very close to zero.
And I can easily imagine lots of scenarios in which it would be extremely empowering for someone to design an extension and be confident that their feeds would be processed only by software that knows it.
And a decision to leave this out feels like hubris to me. "We're so sure we got the core right that we can leave out an extremely cheap potentially-valuable extension point." I doubt it.
-Tim
