There are a collection of software projects underpinning the infrastructure of the transaction supply chain.  A proposal here would focus on a feature request or bug fix for any of the linked repos:

• https://github.com/flashbots/mev-boost
• https://github.com/flashbots/mev-boost-relay
• https://github.com/flashbots/builder
• https://github.com/ralexstokes/mev-rs
• https://github.com/ultrasoundmoney/reth-payload-validator
• https://github.com/ultrasoundmoney/mev-boost-relay
• https://github.com/ultrasoundmoney/block-submission-service
• https://github.com/ultrasoundmoney/mouseion

Note: a successful proposal will likely be a larger, coherent proposal to implement some feature or concrete improvement.  This is not a request for funds simply to fix a medley of bugs (although discussion around specifics can be had).