second tier tax
(1) Right to bring actions (A) In general With respect to any taxable event, payment of the full amount of the first tier tax shall constitute sufficient payment in order to maintain an action under this section with respect to the second tier tax. (B) Definitions For purposes of subparagraph (A), the terms “taxable event”, “first tier tax”, and “second tier tax” have the respective meanings given to such terms by section 4963.
26 USC § 7422(g)(1)
None identified, default scope is assumed to be the parent (subchapter B) of this section.