Spent some time reading the most recent legislative acts. Of note from H.J.Res.31 - Consolidated Appropriations Act, 2019 is this little blurb speaking to the allocation of government funds:

SEC. 528.

(a) None of the funds appropriated or otherwise made available in this or any other Act may be used to construct, acquire, or modify any facility in the United States, its territories, or possessions to house any individual described in subsection (c) for the purposes of detention or imprisonment in the custody or under the effective control of the Department of Defense.

(b) The prohibition in subsection (a) shall not apply to any modification of facilities at United States Naval Station, Guantanamo Bay, Cuba.

Given that the DoD has many detention facilities spread across the globe, why is GITMO the only one that can receive funding from this bill? Could be due to needing some renovations prior to placing a few treasonous folks behind those bars.