В Fri, 3 Jul 2020 21:53:44 +0500
Dmitry Petukhov via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
wrote:

> My hope is that having a clear specification and (possibly, in the
> future) permissibly licensed quality implementations would make
> adopting such format easier for vendors.

I have added a C implementation (MIT-licensed):
https://github.com/dgpv/bip32_template_c_implementation