At AirVenture 2021, General Aviation Modifications Inc. was awarded an STC for its unleaded 100-octane fuel. Here's an interview with GAMI's George Braly and Tim Roehl and Craig Sincock of Avfuel explaining the details.
This is a companion discussion topic for the original entry at https://www.avweb.com/multimedia/airventure-2021-gami-g100-fuel-in-detail