If you want change chances and possible outcomes, you need to edit files located there:  
[1.21-1.21.4] - 48-61/data/aruturyuu/loot_table  
[1.21.5-1.21.10] - data/aruturyuu/loot_table  
Dimensions: 
0 - overworld  
1 - the_nether  
2 - the_end  
3 - any other dimensions