29 C.F.R. § 1208.3
The NMB shall, in conformance with 5 U.S.C. 552(a)(2) , maintain and make available for public inspection, by posting on its Web site (unless the Board determines by order published in the FEDERAL REGISTER that such publication would be unnecessary or impracticable) the following information: Final opinions, including concurring and dissenting opinions made in representation cases; statements of policy and interpretation made by the NMB but not published in the FEDERAL REGISTER; administrative staff materials, such as the Representation Manual; frequently requested materials, defined as those released in response to a FOIA request and for which the Agency has received at least three requests or those records that because of the nature of their subject matter the Agency determines are likely to become the subject of subsequent requests; and a general index of records available under this section.
29 C.F.R. §1208.3