> At least OpenBSD, when it says it supports a platform, _actually supports that platform_

I always thought it was cool OpenBSD compiled on each arch itself. IIRC, there is or was a rack of servers, each with a unique architecture that all built their respective release files. The various targets could help catch arch-specific bugs leading to more portable code.

VAX was always last and the slowest, which was part of why VAX support was dropped some time ago.