In a similar fashion, you'll see that JAX has frontend code being open-sourced, while device-related code is distributed as binaries. For example, if you're on Google's TPU, you'll see libtpu.so, and on macOS, you'll see pjrt_plugin_metal_1.x.dylib.

The main optimizations (scheduler, vectorizer, etc.) are hidden behind these shared libraries. If open-sourced, they might reveal hints about proprietary algorithms and provide clues to various hardware components, which could potentially be exploited.

And people say nvida doesn't have a moat.

donno. it's clear they have no effective moat. they still try hard, making themselves quite customer-hostile.

CUDA is a moat. What's ineffective about it?