well, yes i am. without any additional magic it might look like:

class ListOptions(Subsystem):
  """Lists all targets matching the target specs.

  If no targets are specified, lists all targets in the workspace.
  """

  options_scope = 'list'

  @classmethod
  def register_options(cls, register):
+---  9 lines: super(ListTargets, cls).register_options(register)-----------

  def __init__(self, options):
    super(ListTargets, self).__init__(*args, **kwargs)
    self._provides = options.provides
    self._provides_columns = options.provides_columns
    self._documented = options.documented


@rule(ListOptions, [])
def list_options():
  scoped_options = yield Get(ScopedOptions, Scope(str(ListOptions.options_scope)))
  return ListOptions(scoped_options)

@witty-crayon-22786 the example seems to be using ListOptions and ListTargets interchangeably. Can you clarify? Is this a subsystem containing what we would today call task options?

Yea!