Haiku is about to get Crossgen2/NativeAOT support: https://github.com/dotnet/runtime/pull/127431
One of the steps involved is to define a 16-bit magic OS-specific constant for Haiku to the PE binary format extension used by Crossgen2.
I am currently choosing 0x0B05 (a reference to OpenBeOS), but I think it might be better for us to decide this together as a community 