##other for anyAttribute

I was trying to figure out what 

 <anyAttribute namespace="##other"/>

means.  Suppose my target namespace is "http://www.example.com", and
suppose I have an element "foo" in that namespace which declares
<anyAttribute namespace="##other"/>.

My reading of the spec was that:

  <eg:foo eg:xyzzy="whatever" xmlns:eg="http://www.example.com"/>

would not be valid, but

  <eg:foo xyzzy="whatever"/>

would be valid, which is not what I would expect (and apparently not
what XSV implements).  So I guess I'm missing something in the spec.

James