Wow, that's crazy - this is/was an internal project of the (now defunct) Resolver Systems [1] - now pivoted to Python Anywhere [2].

I remember working briefly on this when I was pairing with William - it does indeed implement the C ABI in C sharp. The rationale behind it was to make numpy work in Resolver One, which was a Pythonic spreadsheet. Sad that it was shelved - it was a nice product.

This looks like a fork, you can read more about it in the (linked from github) Google Code page: https://code.google.com/archive/p/ironclad/

[1]: http://www.resolversystems.com [2]: https://www.pythonanywhere.com