The Office of Administration was established in 1977 by President Carter, and "[p]roved[es] effective, efficient and economical administrative and business services to the Executive Office of the President." The Office actually comprises seven offices, including the Office of the Chief Financial Officer, Office of the Chief Information Officer, and Office of the General Counsel. In other words, if you want to know what's happening at the White House, the Office of Administration is the place to go.
In 2009, the United States District Court for the District of Columbia found that the Office of Administration was not subject to FOIA. Citizens for Responsibility & Ethics in Wash. v. Office of Admin., 566 F.3d 219, 220 (D.C. Cir. 2009) ("We conclude that the Office of Administration is not [subject to FOIA] because it performs only operational and administrative tasks in support of the President and his staff and therefore, under our precedent, lacks substantial independent authority."). The key issue in Citizens was whether the Office of Administration was an "agency" under FOIA. The court found that it was not an agency because it did not "wield[] substantial authority independently of the President."
Notwithstanding the 2009 decision, as well as various White House policies that claimed an exemption to the Act under Presidents Bush and Obama, the White House has voluntarily released records in response to various public records requests over the years. Now, however, the rule change seems to indicate that the Office of Administration will act in exemption from the Act – no longer releasing any records, voluntarily or otherwise.