This section explains how ARC loads AUP into a session, chooses a renderer, and applies support/degradation behavior, while keeping Web Device, frames, and embedded surfaces as distinct boundaries.
Read in this order
- Renderers, sessions, and support for the target/transport boundary.
- Custom primitives and Web widgets before treating a parser-accepted name as portable.
- AUP on Web Device for the static-tree versus Web-layout distinction.
- Frames, bridges, and embedded surfaces for same-origin and trust boundaries.