He's hardly the first person to do this. Often when people do this it causes real problems, as most people aren't lawyers and sometimes their edits have unintended consequences. It also tends to mean that reusers have to re-evaluate if the trivial change affects them, possibly get separate legal approval if they are in a company, etc. Tends to just cause a huge headache. Anyways, I'm sure Daniel meant no harm with this, but i still think people should be strongly discouraged from doing that sort of thing.
Because now, see, you need an army of very expensive lawyers to very carefully analyze the changes to determine if you can still be using the thing. The answer is always tricky, boils down to “it depends, now pls give us more of those sweet hourly fees and your own project description in detail so we may determine if maybe probably it’s ok in your particular case. Not guaranteed, of course, gotta have a court case to guarantee anything.”
So legally tricky, much legal busywork. Very courageous.
> It is an MIT license that I was unclever enough to slightly modify many years ago
(emphasis mine)