RFPs are used by various organization to receive bids on a specific project. They are often kept confidential during the bidding process but after a Proposal has been accepted and awarded, parts or all of accepted proposal may be made publicly available. There are often many ethical or conflict of interest rules associated with RFPs. This RFP was posed by a UIUC research group seeking ideas for games, VR, and simulation software for improved community healthcare.
Proposals are documents are submitted in response to the requests for proposals (RFP), defined above. They document a service design, improvement, or ongoing contractual process addressing a specific need outlined in the RFP. Often confidential during the bidding process, after being selected and awarded, parts or all of accepted proposals may be made publicly available.
For example, you can read about proposed MCORE project to improve the streets of Urbana here.