Resting in my armchair, I think they're trying to make deals with several other banks to absorb the SVB clientele. Maybe there's one bank that agrees to buy up a large chunk of the deposits and a couple smaller ones that participate as well. If there are multiple buyers, it spreads out risk and doesn't just give assets to a big big, and may help raise the price floor. The FDIC might cover the gap.
I don’t believe the FDIC has the legal authority to do so, but it’s highly possible that the treasury and/or Federal Reserve can cobble together some ad hoc legal justification.
It could be as simple as the fed purchasing a large long dated convertible note with very favorable terms from the new entity created for receivership and then turning around and selling that entity to another bank, now that the balance sheet is fine. Or the conceptual equivalent.
"FDIC - Deposit Insurance FAQs" https://www.fdic.gov/resources/deposit-insurance/faq/
If the fdic has any sense they’ll announce up front the exact figures though and announce it is close to 100% for depositors to make sure this is contained, ideally through a sale to another bank, if not they’ll have to run it. Bondholders and shareholders and svb employees get wiped out.