Financing for the ambitious project that also could provide a strong link between the XL Center and Main Street still needs to be lined up. The developers brought the proposal to CRDA — the quasi-state agency that has been the driving force behind downtown conversions in the past five years — seeking $20 million in public subsidy. In projects it approves, CRDA typically extends loans or equity investments. The developers also will seek historic credits as part of the financing, they said.