Compiled against Escape From Tarkov 0.13.5.26535, for SPT AKI version 3.7.6.
Simply extract the zip file contents into your root SPT-AKI folder (where EscapeFromTarkov.exe is).
Your BepInEx/plugins folder should now contain a RaiRai.HiddenCaches.dll file inside.
This is a backport for SPT AKI 3.7.6, please do not use this release if you are not using the above-mentioned client version.
(To download, click "Assets" right below here to expand the options, and download the zip file - not the source code!)