Bindings between boa-cat (JS engine) and the DOM (html-cat tree) plus fetch (net-cat). v0.7.10 honours the spec's `cancelable` gate on `preventDefault()`: the method now only flips `defaultPrevented` when `this.cancelable === true`. Default-constructed events (plain `{type: 'foo'}` literals, or `new Event(type)` without explicit options) are NOT cancelable and `preventDefault` is a silent no-op on them; scripts must opt in via `new Event(type, { cancelable: true })` or `{ type, cancelable: true }`. Seventh sub-crate of a Servo-replacement webview runtime targeting Tauri.