It was introduced back then with .NET Framework 4.6 (C# 6) - a loong time ago (July 2015). The OSS .NET has started with Roslyn from the very beginning.

> And the Java AOT compiler (native image) is not only fully written in Java itself, everything from optimizations to code generation, but even the embedded runtime is written in Java too.

NativeAOT uses the same architecture. There is no C++ besides GC and pre-existing compiler back-end (both ILC and RyuJIT drive it during compilation process). Much like GraalVM's Native Image, the VM/host, type system facilities, virtual/interface dispatch and everything else it could possibly need is implemented in C# including the linker (reachability analysis/trimming, kind of like jlink) and optimizations (exact devirtualization, cctor interpreter, etc.).

In the end, it is the TypeScript team members who worked on this port, not Anders Hejlsberg himself, which is my understanding. So we need to take this into account when judging what is being communicated.