calculus and analysis – Series of inverse functions, unclear numerical constant


I was answering another question here and came up with this simple illustrative example that should have an analytic solution. Indeed it has, but I do not understand it. In particular, where 85 is coming from?

g[x_]:=BesselJ[0,x]
f[x_]:=Exp[x]
Series[f[InverseFunction[g][y]],{y,0,0}]
Out[1]= E^-BesselJZero[0,85]+O[y]^1