FriCas seems to be quite light in documentation?
Also built-in help with ")help ...": https://fricas.github.io/help.html
draw(5*besselJ(0,sqrt(x^2+y^2)), x=-20..20, y=-20..20)
On macos, it says "transmitting data", but nothing shows. Will visit again if/when out of Beta, it would be great to have a working version of Axiom.