Can he breathe fire? It says "racial hit dice", but kobolds don't have any, right?
if it doesn't have racial hit dice you cant use the breath weapon cause it won't be able to do damage this also means you won't have the elemental immunity since you won't technically have a breath weapon.
But you still do have a breath weapon - it just doesn't do damage. The damage may be tied to racial hit dice, but simply having the breath weapon isn't.
Edit: But see my next post below. It may do damage.
More just for show than a weapon, then.
Actually, it would do 1d6 damage according to James Jacobs. Link