G4NDL file format and altering physics constructors to add cross section data

I’m attempting to add cross section files to be used by NEUTRONHP to include temperature-dependent neutron capture cross section datasets as well as ENDF data for nuclei that are not currently in G4NDL. I see I can set my environmental variable to point to the location of the .z files which leads me to 2 questions.

The first is, what is the G4NDL file format? When I decompress a .z file I see a file with 6 columns (excerpt below). The first, third, and fifth columns appears to be energy with the second, fourth, and sixth being cross sections. I assume this is cross section and error? Additionally what is the format of the FS and FSMF6 files for the capture cross section data sets? I cannot find any documentation talking about formatting and it appears I will need to create my own files.
Excerpt of file:
1.000000e-05 6.873897e+03 1.031250e-05 6.768949e+03 1.062500e-05 6.668666e+03
1.093750e-05 6.572712e+03 1.125000e-05 6.480785e+03 1.156250e-05 6.392610e+03
1.187500e-05 6.307938e+03 1.218750e-05 6.226545e+03 1.250000e-05 6.148224e+03
1.281250e-05 6.072785e+03 1.312500e-05 6.000058e+03 1.343750e-05 5.929882e+03
1.375000e-05 5.862112e+03 1.437500e-05 5.733264e+03 1.500000e-05 5.612556e+03
1.562500e-05 5.499164e+03 1.625000e-05 5.392379e+03 1.687500e-05 5.291583e+03
1.750000e-05 5.196236e+03 1.812500e-05 5.105865e+03 1.875000e-05 5.020050e+03
1.937500e-05 4.938423e+03 2.000000e-05 4.860652e+03 2.093750e-05 4.750592e+03
2.187500e-05 4.647685e+03 2.281250e-05 4.551189e+03 2.375000e-05 4.460465e+03
2.468750e-05 4.374959e+03 2.562500e-05 4.294190e+03 2.656250e-05 4.217735e+03
2.750000e-05 4.145224e+03 2.843750e-05 4.076330e+03 2.937500e-05 4.010760e+03
3.031250e-05 3.948256e+03 3.125000e-05 3.888587e+03 3.218750e-05 3.831544e+03
3.312500e-05 3.776940e+03 3.406250e-05 3.724607e+03 3.500000e-05 3.674390e+03
3.593750e-05 3.626152e+03 3.687500e-05 3.579765e+03 3.781250e-05 3.535114e+03
3.875000e-05 3.492093e+03 3.968750e-05 3.450607e+03 4.062500e-05 3.410564e+03
4.250000e-05 3.334492e+03 4.437500e-05 3.263294e+03 4.625000e-05 3.196471e+03
4.812500e-05 3.133592e+03 5.000000e-05 3.074284e+03 5.156250e-05 3.027353e+03
5.312500e-05 2.982508e+03 5.468750e-05 2.939599e+03 5.625000e-05 2.898490e+03
5.781250e-05 2.859060e+03 5.937500e-05 2.821196e+03 6.093750e-05 2.784799e+03
6.250000e-05 2.749775e+03 6.406250e-05 2.716040e+03 6.562500e-05 2.683518e+03
6.718750e-05 2.652137e+03 6.875000e-05 2.621832e+03 7.187500e-05 2.564214e+03
7.500000e-05 2.510236e+03 7.812500e-05 2.459531e+03 8.125000e-05 2.411780e+03
8.437500e-05 2.366707e+03 8.750000e-05 2.324071e+03 9.062500e-05 2.283660e+03
9.375000e-05 2.245287e+03 9.687500e-05 2.208786e+03 1.000000e-04 2.174010e+03
1.031250e-04 2.140827e+03 1.062500e-04 2.109119e+03 1.093750e-04 2.078780e+03
1.125000e-04 2.049714e+03 1.156250e-04 2.021835e+03 1.187500e-04 1.995064e+03

My second question is, I saw in another question someone referenced being able to alter the physics constructors to accept different cross section files which strikes me as a more user friendly way to achieve what I am after. Are there any examples for that?

Thank you all!