“Official” support for Windows was discontinued, see Looking for community support for the Windows build for the explanation and discussion. Fixing the downloads page to not list Windows for recent releases is on @ammolitor’s todo list, but he’s previously commented that there’s higher priority items for him to tackle first. I didn’t see an issue specifically tracking this work, so I filed Officially discontinue the Windows build · Issue #5135 · apple/foundationdb · GitHub.
There were a few changes done to enable FDB to work under the Windows Subsystem for Linux, which was reported as working FoundationDB does not run on Windows Subsystem For Linux (WSL) - #10 by KrzysFR.