/**
 * Which Lit DevTools runtimes are on this page, and which one serves it.
 *
 * Three can load one: the plugin's, served through Vite; the Lit Inspector
 * extension's, injected at `document_start` on a site the user enabled; and
 * the `lit-devtools dev` script. Each brings its own copy of the runtime
 * modules, but they share every page global keyed by `Symbol.for`, the page
 * channel among them. Two installed side by side step on each other: two
 * inspectors answer every command, two pickers fight over one element name
 * and one toggle. That happens when the extension is enabled for a dev
 * server the plugin already runs on.
 *
 * So the first runtime to join serves the page, and a later one only adds
 * its carrier to the shared channel: the Vite-served modules check
 * {@link yieldsToAnotherRuntime} before they install. The extension is always
 * first, injected ahead of the page's scripts.
 *
 * Each runtime joins under its kind, the Vite-served one from every module
 * (`pageChannel.useViteHot()`), the others from their entry; joining again
 * under a kind counts once. A second kind is noted once in the console and
 * reported to the panels (the inspector's `ready`).
 *
 * @module
 */
import { type PageRuntimeKind } from '../../types/inspector.js';
export type { PageRuntimeKind };
/** The runtimes on this page, in the order they joined; the first serves it. */
export declare const runtimesOnPage: () => readonly PageRuntimeKind[];
/**
 * Whether this copy of a runtime module should install nothing: it is the
 * Vite-served runtime's, which `import.meta.hot` gives away (pass it in),
 * and another runtime joined the page first. It still adds its carrier.
 * The extension's and the script's copies have no `hot` and always install.
 */
export declare const yieldsToAnotherRuntime: (hot: unknown) => boolean;
/**
 * Run `callback` whenever another runtime joins the page. Every copy of the
 * runtime hears it, the one that joined first included.
 */
export declare const onRuntimeJoined: (callback: () => void) => void;
/** Add `kind` to the page's runtimes. Joining again under a kind is a no-op. */
export declare const joinPage: (kind: PageRuntimeKind) => void;
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