What's the current story on how it maps to system accessibility mechanisms? The high-level components for marking objects up with accessibility data look fine.
Depends on the backend.
With our main backend (the winit backend) it uses AccessKit [https://github.com/AccessKit/accesskit]
With our Qt backend (used for the Qt native style on Linux), it uses Qt accessibility infrastructure.
The 'a' in imgui stands for accessibility.
Sometimes, it's useful to have a quick and dirty GUI toolkit. I think Slint fills that gap.