Examine source code of Christmas

{
  "name": "Christmas",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "christmas_new_year_winter_130938_1600x900.jpg"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(105, 111, 224, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f47adefe-f9d3-406a-8362-2e3ba1485897}"
    }
  }
}