@adamgreenfield all of those things, yes. It's weather protection plus structural integrity plus crash safety capsule plus aerodynamics. It is the main structure of the vehicle — it has to be, anything else would be to heavy. It's intended to be a carbon fibre/nomex/aramid composite;

More detail here (although I've now had advise that it's unwise to put the aramid layer on the outside)

#BikeTooter

https://www.journeyman.cc/blog/posts-output/2024-09-11-Thoughts-on-bent-cycles/#composites