Liskov's explanation at a talk she gave a couple years ago was that it just looked like the obvious way one ought to use subtyping and certainly not a deep enough insight to be worth naming.

It’s possible. Part of the story is that someone gave her the idea and then she gave a talk about it, not citing that person, and then everyone just assumed it was her idea.

Lesson to folks in a leadership position with smart folks reporting to them: let them present their own ideas and get the credit. If you present their idea for them, make abundantly clear it’s their idea not yours.