Examine source code of Purplish for Firefox

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Purplish for Firefox",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-003-31b6bea3c78e3a19fd889b0389652a94.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(187, 178, 233)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(142, 179, 201)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(11, 11, 111)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgb(108, 108, 157)",
      "popup_text": "rgb(0, 0, 0)",
      "tab_loading": "rgb(0, 0, 0)"
    }
  }
}