Deprecation marks vs. module augmentation (https://github.com/microsoft/vscode-docs/blob/vnext/release-notes/v1_39.md#deprecation-tags-for-symbols-and-completions)

deprecation-augmentation.ts

declare global {
  interface DOMRect extends DOMRectReadOnly {
    /**
     * @deprecated Doesn't work on legacy Edge. Use `left` instead.
     */
    x: number;
    /**
     * @deprecated Doesn't work on legacy Edge. Use `right` instead.
     */
    y: number;
    /**
     * @deprecated Grrr
     */
    z: number;
  }
}

const { x, y, z } = document.body.getBoundingClientRect();

export {}