Need some explanation in Blasius and Falkner-Skan.jl

[SoumyaKedia]

in Blasius and Falkner-Skan.jl f = (u)->(2.0*D^3*u + 3*u*D^2*u) df = (u)->(2.0*D^3 + u*D^2 + D^2*u)

Shouldn't it be df = (u)->(6.0*D^2 + D^2*u + 2*u*D*u)

Other thing is, global u -= [B; df(u)]\[u(0.);u'(0.);u'(rightendpoint(d))-1.;f(u)] What is happening in this line of code?