Judging by the name RungeKutta62, named after a class of numerical integration methods and thus two mathematicians, I’d say they’re a nerd themselves.

Well, as the URL says, that’s logistic growth and not exponential growth.

A .tar.gz is a regular archive, the file manager shouldn’t assume it’s a program. Also, how do you expect it to work? There’s no general rule for archives. As for appimages, one of their selling points is that you can run them portably, so it shouldn’t install by default, but run. However, a right click install option would be nice.