The explanation is as follows:
SUMMARY: This notice is provided in accordance with IRC section 6039G of the Health Insurance Portability and Accountability Act (HIPPA) of 1996, as amended. This listing contains the name of each individual losing United States citizenship (within the meaning of section 877(a) or 877A) with respect to whom the Secretary received information during the quarter ending September 30, 2012. For purposes of this listing, long-term residents, as defined in section 877(e)(2), are treated as if they were citizens of the United States who lost citizenship.For a chart showing the renouncers over the years 2005 to present, see Andrew Mitchel's International Tax Blog here.
Hat tip to Tax Prof Blog, here.