There's a merged pull request on the void-packages repository

New package: b43-firmware, b43-firmware-classic
https://github.com/void-linux/void-packages/pull/22160

Description:
These are restricted templates (proprietary, non-redistributable) for broadcom b43 series wireless hardware (used in various laptops etc., notably Apple PowerPC and early Intel, but also others)

I haven't been able to find the license text.

Based on the Arch pkgbuilds and Gentoo ebuild.