Return information

U.S. tax code
Return information, in general, is

"any information collected or generated by the IRS with regard to any person’s liability or possible liability under the IRC. IRC 6103(b)(2)(A) defines return information as very broad. It includes but is not limited to:

such as name, address, and identification number are deleted
 * Information, including the return, that IRS obtained from any source or developed through any means that relates to the potential liability of any person under the IRC for any tax, penalty, interest, fine, forfeiture, or other imposition or offense
 * Information extracted from a return, including names of dependents or the location of business
 * The taxpayer’s name, address, and identification number
 * Information collected by the IRS about any person's tax affairs, even if identifiers,
 * Status of whether a return was filed, under examination, or subject to other investigation or processing, including collection activities
 * Information contained on transcripts of accounts."