I noticed after checking out several models, they contain several modelling errors.
I don't know if they are commonly known already, but I'll mention them anyway.
For example, Arachna seems to have some second head mounted on her back which appears in the die animation.
Another example is Penguin, which has some odd vertices near in the middle of his pants. This isn't very sightable ingame often due the darkness of the atmosphere of maps and the appearance of Penguin, but it is very clear when you would import them to any other game platform which supports the .md3-format.
I'm sure there are pretty much more, but these are the ones which I've found the quickest.