You know this is easily verifiable right…. I just put 10 random pages into Pangram and they all came back 100% human. And now I feel bad for making an even greater proportion of comments on this thread not about graph theory.
My anecdotal experience has been that is is very reliable on inputs over 500 words. There are a number of third party evaluations that corroborate. Pangram is pretty easy to test for yourself if you are a skeptic.
Pangram is very good if you can provide enough text, in my experience.
I wouldn't use it as a 100% infallible AI detector when the stakes are high (accusing someone of cheating) but it's very good at detecting AI generated text when you can drop large sections of text into it.