That headers looks pretty reasonable to me. I don't see anything misleading or ambiguous about it. Whenever I am heavily modifying some licensed code, I always make sure to include a similar header.

    > I'm going to ahead and say there are copyright law nightmares, right here.

I am confused. My first thought was maybe the original Linux driver was GPL'd, but it is not. It is ISC'd. Look here: https://github.com/torvalds/linux/blob/master/drivers/net/wi...

    // SPDX-License-Identifier: ISC
    /*
     * Copyright (c) 2010 Broadcom Corporation
     */

It adds a contributor.

To add a contributor, you need "significant" _human_ input. The output of models has so far not been deemed copyrightable.

As it acknowledges the original source, it needs to show the human effort that allows it to be bound to the new contributors.

Eh. Copyright only matters if it goes to court. And you only go to court over copyright if somebody is getting sued. That only happens when a plaintiff has standing, they can show damages and the person they want to sue has enough money to make it worth their while. (And if they'll make more money than it costs them in lawyers and negative PR. Suing users and developers for interacting with the product you sold them is generally considered a bad look.)

Anyway, nobody is going to sue you because you added your name (or "project contributors") to an ISC licensed source file in your own repository. Nobody cares. And there's no damages anyway.

Especially when the line added is:

> Copyright (c) brcmfmac-freebsd contributors

If you're right, that's an empty category. Thus the inclusion has no effect.