If you maintain a GObject-based library or a language binding, and have 25 minutes to spare for reading ~5700 words on a possible new direction for the GObject type system, I wrote something that might interest you: https://www.bassi.io/articles/2023/08/23/the-mirror/
It's a strawman proposal, and it needs a lot more discussion with various stakeholders; ideally, we're going to have a hackfest about GObject, language bindings, introspection, and the future of the type system.