KmPlot is unmaintained, it shares a lot of code with KAlgebra, it makes sense to get this shared code in a lib so that KmPlot will be maintained and both programs work (that's Percy GSoC).
The idea behind KAlgebra is that the user should understand the application by using it and not by reading the manual. KAlgebra can calculate, it can have functions for that (a Fibonacci function as example). It can plot, both 2D and 3D.
Remaining question: how to get content in KAlgebra?