It probably depends on what mod you were using and how the mods decided to do it.

What I'm guessing happened is that the mods you were using replaced the recipes for tools to instead craft the same tool but with additional NBT to change the attributes. In which case, the "Altered Armor Values" are all stored on the end result items themselves, individually. The values wouldn't be connected to any setting in a world file, just somewhere in your <player>.dat or the region file there's an inventory that has a minecraft:iron_axe({AttributeModifiers:[{AttributeName:"generic.attack_damage", Name:"generic.attack_damage", Amount:2048, Operation:0, UUID:[I; 42853, 1689024593, -201178, -1559272105]}]} 1 which is unique amount all other iron axes in the game, even those that also have max damage.