How constraint type is populated in foundation form text component??

HI Guys

            When i was analysing foundation/components/form/text component i could see that the constraintType is populated from /bin/wcm/foundation/forms/constraints.json . When i am creating a custom text component in apps/<proj>/components/ with same structure it is not getting populated. Where does this /bin/wcm/foundation/forms/constraints.json refer to? I couldnt find any bin folder in my CRXDE. Any help would be appreciable

Thanks

Veena