Here we compare the difference in grib_ls for pre-existing sub-hourly data.

1. DWD

ecCodes < 2.34.0 
grib_ls -p param,step,stepUnits:s,startStep,endStep,stepRange DWD*

DWD_icon-d2_germany_icosahedral_single-level_2023092600_000_2d_tmax_2m.grib2
param       step        stepUnits   startStep   endStep     stepRange   
201         0           m           0           0           0          


DWD_icon-d2_germany_icosahedral_single-level_2023092600_000_2d_tot_prec.grib2
228228      0           m           0           0           0          
228228      15          m           0           15          0-15       
228228      30          m           0           30          0-30       
228228      45          m           0           45          0-45       


DWD_icon-d2_germany_icosahedral_single-level_2023092600_048_2d_tmax_2m.grib2
201         2880        m           2520        2880        2520-2880  


DWD_icon-d2_germany_icosahedral_single-level_2023092600_048_2d_tot_prec.grib2
228228      2880        m           0           2880        0-2880     


DWD_icon-d2_germany_icosahedral_single-level_2023092800_000_2d_t_2m.grib2
167         0           m           0           0           0          


DWD_icon-d2_germany_icosahedral_single-level_2023092800_048_2d_t_2m.grib2
167         2880        m           2880        2880        2880  
ecCodes >= 2.34.0 
grib_ls -p param,step,stepUnits:s,startStep,endStep,stepRange DWD*

DWD_icon-d2_germany_icosahedral_single-level_2023092600_000_2d_tmax_2m.grib2
param       step        stepUnits   startStep   endStep     stepRange   
201         0m          m           0m          0m          0m         


DWD_icon-d2_germany_icosahedral_single-level_2023092600_000_2d_tot_prec.grib2
228228      0m          m           0m          0m          0m         
228228      15m         m           0m          15m         0m-15m     
228228      30m         m           0m          30m         0m-30m     
228228      45m         m           0m          45m         0m-45m     


DWD_icon-d2_germany_icosahedral_single-level_2023092600_048_2d_tmax_2m.grib2
201         48          h           42          48          42-48      


DWD_icon-d2_germany_icosahedral_single-level_2023092600_048_2d_tot_prec.grib2
228228      48          h           0           48          0-48       


DWD_icon-d2_germany_icosahedral_single-level_2023092800_000_2d_t_2m.grib2
167         0m          m           0m          0m          0m         


DWD_icon-d2_germany_icosahedral_single-level_2023092800_048_2d_t_2m.grib2
167         48          h           48          48          48

2. HARMONIE

ecCodes < 2.34.0 
grib_ls -p param,step,stepUnits:s,startStep,endStep,stepRange HARMONIE*

HARMONIE_fc2023082412+005h15mgrib2_fp
param       step        stepUnits   startStep   endStep     stepRange   
130         315         m           315         315         315        
54          315         m           315         315         315        
ECCODES ERROR   :  unable to convert endStep in stepUnits
178         step (Wrong units for step (step must be integer))
ecCodes >= 2.34.0 
grib_ls -p param,step,stepUnits:s,startStep,endStep,stepRange HARMONIE*

HARMONIE_fc2023082412+005h15mgrib2_fp
param       step        stepUnits   startStep   endStep     stepRange   
130         315m        m           315m        315m        315m       
54          315m        m           315m        315m        315m       
178         315m        m           0m          315m        0m-315m

3. MET EIREANN

ecCodes < 2.34.0 
grib_ls -p param,step,stepUnits:s,startStep,endStep,stepRange MET_EIREANN*

MET_EIREANN_fc2023083006+000h15mSUB_HOURLY_CT_grib2_HIoI
param       step        stepUnits   startStep   endStep     stepRange   
54          15          m           15          15          15         
228141      15          m           15          15          15         
ECCODES ERROR   :  unable to convert endStep in stepUnits
260058      step (Wrong units for step (step must be integer))
ecCodes >= 2.34.0 
grib_ls -p param,step,stepUnits:s,startStep,endStep,stepRange MET_EIREANN*

MET_EIREANN_fc2023083006+000h15mSUB_HOURLY_CT_grib2_HIoI
param       step        stepUnits   startStep   endStep     stepRange   
54          15m         m           15m         15m         15m        
228141      15m         m           15m         15m         15m        
260058      15m         m           0m          15m         0m-15m     
260049      15m         m           0m          15m         0m-15m