This is the location of the model files.
..\SpellBinder\src\main\resources\assets\spellbinder\models\item\ingot_brass.json
which as far as I am aware equals
spellbinder:models/item/ingot_brass.json
You are looking at the texture file.
After looking at examples on Github. I believe that folders in the 'models' folder are singular and folders in the 'textures' folder are plural.
Please correct me if I am wrong.