Examine source code of Nightly Lights

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "NightlyLights",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(255, 255, 255, 0)",
      "toolbar_field": "rgba(0, 0, 0, 0.2)",
      "toolbar_field_text": "rgb(237, 237, 237)",
      "tab_line": "rgb(237, 237, 237)",
      "popup": "rgb(237, 237, 237)",
      "popup_text": "rgb(44, 44, 44)",
      "tab_loading": "rgb(237, 237, 237)",
      "bookmark_text": "rgb(237, 237, 237)",
      "frame": "rgb(44, 44, 44)",
      "tab_background_text": "rgb(44, 44, 44)"
    }
  }
}