Lanefan
Victoria Rules
The dungeon version of Braunstein may have had some mechanical resolution but the live-action version (which I've played with the game's inventor) is pretty much free-narration resolution. Each player has in-character goals for their character as advised before play begins; the players then do what they can to achieve those goals while also attempting to first realize there's a mystery involved and then solve it. At the end the GM - who has otherwise done nothing all afternoon except enjoy the entertainment and answer a few questions - tells us what we did right in character and where-how we messed up in solving the mystery (our lot missed it by miles).But my understanding of the Braunstein, and the dungeon version of it, is that it is all about the fiction - drawing on the established fiction to make new fiction that advances one's position - with mechanical elements (eg that door might be stuck - roll a die to see if you can force it) being secondary. The non-mechanical rules, as I understand it, were basically carried over from free narration resolution in wargaming.
It's actually much closer to LARP - e.g. different locations in the room stand in for different locations in the setting and you have to move to a location in order to talk to someone there - than to what we now know as TTRPGs.