Does anyone know how to add new "WeaponClassType" definitions?

Example;

Weapon
 WeaponType "Projectile"
 damageEnums
  AttackType "ANTIHEAVY"
  DamageAffectType "AFFECTS_SHIELDS_AND_HULL"
  DamageApplyType "BACKLOADED"
  DamageType "ENERGY"
  WeaponClassType "LASERTECH"

All the string IDs seem to be linked to this value and so are the Research Adjustments but there are no entity files linking the ClassType to the English.str and the Weapon entity file is empty.

Are these hard-coded? Can new ones be added using links in the Weapon.entity file and if so does anyone know the format?