/**
 * Ensure the repo workspace or .vscode settings include Needle Engine custom HTML data if they exist.
 * Copies custom-elements.json to the project and merges with existing user content.
 * - Copies/merges `custom-elements.json` to project root
 * - Adds `./custom-elements.json` to `.code-workspace settings.html.customData`
 * - Adds `./custom-elements.json` to `.vscode/settings.json html.customData`
 * @param {"build" | "serve"} _command
 * @param {import('../types').needleMeta | null} _config
 * @param {import('../types').userSettings} userSettings
 * @returns {import('vite').Plugin | null}
 */
export function needleCustomElementData(_command: "build" | "serve", _config: import("../types").needleMeta | null, userSettings?: import("../types").userSettings): import("vite").Plugin | null;
export default needleCustomElementData;
export type CustomElementData = {
    version?: number;
    tags?: {
        name: string;
        [key: string]: unknown;
    }[];
    valueSets?: {
        name: string;
        [key: string]: unknown;
    }[];
    globalAttributes?: unknown[];
};