The "krz" format was developed as part of a project aimed at self-consistent determinations of abundances in pulsating early-type stars (B to F). This project was carried out at the Institute for Astronomy in Vienna and more details can be found in http://ams.astro.univie.ac.at/ .
An explanation of the .krz format is given below.
Among other things the following issues have been addressed within this project:

• Creation of a complete database of atomic line data (VALD, http://www.astro.uu.se/~vald/ , Kupka et al.: 1999, A&AS 138, 119) used for opacity calculations and spectral synthesis;
• Calculation of model atmospheres consistent with the derived abundances (Piskunov & Kupka: 2001, ApJ 547, 1040);
• Fast and accurate spectral synthesis codes with and without the effects of magnetic fields like SME (Valenti & Piskunov: 1996, A&AS 118, 595) and SYNTHMAG (Piskunov: 1999, in Proc. of Solar polarization workshop, Bangalore, 1998, Nagendra & Stenflo (eds.), Kluwer Astrophysics and space science library, v. 243, p. 515);
• Doppler Imaging of chemical composition and magnetic fields (Piskunov & Kochukhov: 2002, A&A 381, 736).

• the MODEL TYPE will be 3 ( for the plane-parallel models it is 0 (zero) )
• in the listing of the model there will be a sixth column containing the the radial distance from a reference layer (in cm), counted positive outwards of this layer and negative inwards. This reference layer is where the Rosseland optical depth equals 1 in the model (log tau_Ross = 0.0). The stellar radius (at log tau_Ross = 0.0) is given in the corresponding ".mod" format file.

TITLE SDSC GRID [+0.0] VTURB 2.0 KM/S L/H 1.25 UNSCALED
T EFF= 7500. GRAV= 4.5 MODEL TYPE= 0 WLSTD= 5000.
1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 0 0 - OPACITY SWITCHES
0.911 0.089 -10.88 -10.89 -9.44 -3.48 -3.99 -3.11 -7.48 -3.95
-5.71 -4.46 -5.57 -4.49 -6.59 -4.83 -6.54 -5.48 -6.82 -5.68
-8.94 -7.05 -8.04 -6.37 -6.65 -4.37 -7.12 -5.79 -7.83 -7.44
-9.16 -8.63 -9.67 -8.69 -9.41 -8.81 -9.44 -9.14 -9.80 -9.54
-10.62 -10.12 -20.00 -10.20 -10.92 -10.35 -11.10 -10.18 -10.58 -10.04
-11.04 -9.80 -10.53 -9.81 -10.92 -9.91 -10.82 -10.49 -11.33 -10.54
-20.00 -11.04 -11.53 -10.92 -11.94 -10.94 -11.78 -11.11 -12.04 -10.96
-11.28 -11.16 -11.91 -10.93 -11.77 -10.59 -10.69 -10.24 -11.03 -10.95
-11.14 -10.19 -11.33 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -11.92
-20.00 -12.51 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 72
1.494770850E-04, 4892.5, 7.94600E+09, 6.99057E+12, 1.50828E-11,
1.983653960E-04, 4912.0, 9.81300E+09, 9.24075E+12, 1.99378E-11,
2.605118600E-04, 4933.4, 1.21100E+10, 1.20835E+13, 2.60713E-11,
3.383485310E-04, 4954.9, 1.48600E+10, 1.56274E+13, 3.37177E-11,
4.346934090E-04, 4976.9, 1.81400E+10, 1.99941E+13, 4.31392E-11,
5.527391110E-04, 4998.8, 2.20200E+10, 2.53075E+13, 5.46034E-11,
6.962465410E-04, 5020.9, 2.65800E+10, 3.17412E+13, 6.84848E-11,
8.694794060E-04, 5043.1, 3.19500E+10, 3.94671E+13, 8.51541E-11,
1.077280610E-03, 5065.9, 3.82800E+10, 4.86771E+13, 1.05026E-10,
1.325020170E-03, 5089.5, 4.57400E+10, 5.95877E+13, 1.28566E-10,
1.618741570E-03, 5114.0, 5.45800E+10, 7.24517E+13, 1.56322E-10,
1.965294820E-03, 5139.7, 6.50600E+10, 8.75249E+13, 1.88844E-10,
...
or

TITLE MARCS 35 model for MLT convection testing. Vturb 2.0 km/s
T EFF= 6500. GRAV= 2.0 MODEL TYPE= 3 WLSTD= 5000 SPHERICAL, RADIUS= 1.155E+12 cm
1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 0 0 - OPACITY SWITCHES
0.922 0.078 -10.88 -10.89 -9.44 -5.65 -6.26 -4.98 -7.48 -5.80
-7.87 -6.11 -7.67 -6.13 -6.59 -6.50 -6.54 -5.48 -8.96 -7.33
-10.87 -8.74 -10.04 -8.40 -8.65 -6.59 -9.12 -7.81 -7.83 -7.44
-9.16 -8.63 -9.67 -8.69 -9.41 -8.81 -9.44 -9.14 -9.80 -9.54
-10.62 -10.12 -20.00 -10.20 -10.92 -10.35 -11.10 -10.18 -10.58 -10.04
-11.04 -9.80 -10.53 -9.81 -10.92 -9.91 -10.82 -10.49 -11.33 -10.54
-20.00 -11.04 -11.53 -10.92 -11.94 -10.94 -11.78 -11.11 -12.04 -10.96
-11.28 -11.16 -11.91 -10.93 -11.77 -10.59 -10.69 -10.24 -11.03 -10.95
-11.14 -10.19 -11.33 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -11.92
-20.00 -12.51 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 -20.00 56
4.754334316E-02, 4571.6, 1.64024E+09, 3.81952E+12, 7.94416E-12, 2.44799E+10,
6.466705352E-02, 4613.0, 2.50945E+09, 6.46942E+12, 1.34563E-11, 2.27099E+10,
8.941244334E-02, 4662.0, 3.81018E+09, 1.02419E+13, 2.13033E-11, 2.11329E+10,
1.236606389E-01, 4714.4, 5.68486E+09, 1.53860E+13, 3.20032E-11, 1.97191E+10,
1.695764661E-01, 4768.2, 8.31312E+09, 2.21840E+13, 4.61428E-11, 1.84345E+10,
2.299538255E-01, 4821.7, 1.19096E+10, 3.10038E+13, 6.44878E-11, 1.72482E+10,
3.084119260E-01, 4874.9, 1.67679E+10, 4.23195E+13, 8.80230E-11, 1.61355E+10,
...

• 1st line - header
• 2nd line
  • T_eff (K)
  • logg (cgs)
  • model type: 0 - plane-parallel, depth scale - column mass in g/cm²
  • model type: 1 - plane-parallel, depth scale - tau at std wavelength
  • model type: 2 - not used
  • model type: 3 - spherical, depth scale - column mass in g/cm²
  • model type: 4 - spherical, depth scale - tau at std wavelength
  • WLSTD - standard wavelength in Å (relevant for model type 1 and 4)
  • SPHERICAL - the same as model type 3 and 4
  • RADIUS - reference radius in cm
• 3rd line - continuous opacities used in calculations following Bob Kurucz convention
  1. - absorption by H
  2. - absorption by H₂⁺
  3. - absorption by H^-
  4. - Rayleigh scattering by H
  5. - absorption by He
  6. - absorption by He⁺
  7. - absorption by He^-
  8. - Rayleigh scattering by He
  9. - absorption by metals for cool stars (Si, Mg, Al, C, Fe)
  10. - absorption by metals for intermediate stars (N, O, Si⁺, Mg⁺, Ca⁺)
  11. - absorption by metals for hot stars (C, N, O, Ne, Mg, Si, S, Fe 1st to 4th ions)
  12. - Thomson scattering by electrons
  13. - Rayleigh scattering by H₂
  14. - 20. not used
• Lines 4-13 - normalized abundances for the first 99 elements in the periodic table: N_atom/N_all where N are number densities. The sum of all abundances is 1. Positive numbers are fractions while negative numbers are log₁₀ of fractions. The last number in line 13 is the number of depth layers in the model.
• Lines 14 and down are the model data. Plane-parallel models have 5 columns while spherical have 6.
  1. column: depth in column mass or optical depth at standard wavelength
  2. column: temperature in K
  3. column: number density of free electrons in cm^-3
  4. column: number density of all other particles (except electrons) in cm^-3
  5. column: density in g/cm³
  6. column: (spherical model only): height in cm relative to the reference radius given in the header