A governmental unit is authorized to issue limited bonds payable from the debt service extension base, as defined in the Property Tax Extension Limitation Law, as provided in this amendatory Act of 1995. Bonds authorized by Public Act 88-503 and issued under Section 20a of the Chicago Park District Act for aquarium or museum projects shall not be issued as limited bonds. A governmental unit issuing limited bonds authorized by this Section shall provide in the bond ordinance that the bonds are issued as limited bonds and are also issued pursuant to applicable law, other than this amendatory Act of 1995, enabling the governmental unit to issue bonds. This amendatory Act of 1995 shall not change the rate, amount, purposes, limitations, source of funds for payment of principal or interest, or method of payment or defeasance of the bonds that a governmental unit may issue under any applicable law; provided, that limited bonds that are otherwise to be issued as general obligation bonds may be payable solely from the debt service extension base. This amendatory Act of 1995 provides no additional authority to any governmental unit to issue bonds that the governmental unit is not otherwise authorized to issue by a law other than this amendatory Act of 1995.