Most of the Microsoft patches look like changes to tests or build scripts, but making [`u_cleanup` a no-op](https://github.com/microsoft/icu/blob/master/icu-patches/patches/006-MSFT-Pa...) is significant. Unfortunately they don't publish binaries from that repo, they do [publish binaries through NuGet](https://www.nuget.org/packages/Microsoft.ICU.ICU4C.Runtime.win-x64) but I think there are differences between those and the Windows OS builds.