Examine source code of date

{
  "name": "date",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "datebannerfirefox.png"
    },
    "colors": {
      "frame": "rgba(32, 51, 94, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{39d7bad8-0ce6-413d-ad6b-e91f78453b02}"
    }
  }
}