What information does extended trace give in nlsolve jl

Hi,
I am interested in what info does extended trace give in NLsolve.jl.
A particular trace reads as

Iter     f(x) inf-norm    Step 2-norm 
------   --------------   --------------
     0     1.000000e-01              NaN
 * f(x): [0.1, 0.0]
 * g(x): [-30.58680355728619 0.0; 0.0 -1.0]
 * x: [0.0, 0.0]
 * delta: NaN
 * rho: NaN
     1     2.339203e-02     3.269384e-03
 * f(x): [0.02339203027677505, 2.3392030276774175e-7]
 * g(x): [-16.27705485965006 0.0; 0.00014309748697635279 -1.0001430974869765]
 * x: [0.0032693837985623268, 0.0]
 * delta: 1.0
 * rho: 0.945281291947572