I don't think modified by a human is enough. If you take licensed text (code or otherwise) and manually replace every word with a synonym, it does not remove the license. If you manually change every loop into a map/filter, it does not remove the license. I don't think any amount of mechanical transformation, regardless if done by a human or machine erases it.

There's a threshold where you modify it enough, it is no longer recognizable as being a modification of the original and you might get away with it, unless you confess what process you used to create it.

This is different to learning from the original and then building something equivalent from scratch using only your memory without constantly looking back and forth between your copy and the original.

This is how some companies do "clear room reimplementations" - one team looks at the original and writes a spec, another team which has never seen the original code implements an entirely standalone version.

And of course there are people who claim this can be automated now[0]. This one is satire (read the blog) but it is possible if the law is interpreted the way LLM companies work and there are reports the website works as advertised by people who were willing to spend money to test it.

[0]: https://malus.sh/