Here is the list of exemptions from the California Firearm Safety Certification Program.
Currently there are 17 exemptions:
X01 = Special Weapons Permit Holder
X02 = Operation of Law Representative
X03 = Handgun being returned to the owner
X13 = FFL collector with COE (curio and relic firearms only)
X21 = Military - Active Duty
X22 = Military - Reserve
X25 = Military - Honorably Retired
X31 = Peace Officer - California - Active
X32 = Peace Officer - Federal - Active
X33 = Peace Officer - California - Honorably Retired
X34 = Peace Officer - California - Reserve
X35 = Peace Officer - Federal - Honorably Retired
X41 = Carry Concealed Weapon (CCW) Permit Holder
X81 = P.O.S.T. 832 PC (Firearms) Training
X91 = Particular and Limited Authority Peace Officers
X95 = Law Enforcement Service Gun to Family Member
X98 = Valid Hunting License (long guns only)