The built-in type structseq (used by e.g. os.stat() for the stat
structure and by the time module for a time tuple) resembles the new
namedtuple type added to the collections module in 2.6.

It would be nice if these had at least a common ABC if not a shared
implementation.

At the same time I think that in 3.0 we should remove the feature of
"hidden fields" which is used to have structs that behave like
fixed-size tuples even though they have a variable number of named
fields (the list of names varies per platform).  We should deprecate the
use of tuple-unpacking for these (except for the first 6 fields of a
timetuple, perhaps).