What is an RFP in construction, when every county job I see is a sealed bid with a plan room?

I'm a general contractor, and I'm used to seeing county construction jobs as an Invitation for Bid (IFB) where we submit a lump sum, and then there's a public bid opening. But I just saw the City of Jacksonville issue an RFP for a new fire station, NAICS 236220, with a deadline of July 26. They're asking for qualifications and a fee proposal, not a lump sum. This is new to me for a public construction project. Does an RFP mean they're looking for a design-build or a construction manager at risk approach? How does the city decide who wins with this kind of submittal instead of just picking the lowest bid?