It's just a symbolic order, won't actually lead to anything important being released because the agencies have the authority to reject whatever they want. Many of the files have already been destroyed anyways.
See:
Sec. 3. General Provisions. (a) Nothing in this order shall be construed
to impair or otherwise affect:
(i) the authority granted by law to an executive department or agency,
or the head thereof; or
(ii) the functions of the Director of the Office of Management and Budget
relating to budgetary, administrative, or legislative proposals.
(b) This order shall be implemented consistent with applicable law and
subject to the availability of appropriations.
See:
Sec. 3. General Provisions. (a) Nothing in this order shall be construed to impair or otherwise affect:
(i) the authority granted by law to an executive department or agency, or the head thereof; or
(ii) the functions of the Director of the Office of Management and Budget relating to budgetary, administrative, or legislative proposals.
(b) This order shall be implemented consistent with applicable law and subject to the availability of appropriations.