Examine source code of Abyss from Waterfox

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Abyss for Firefox",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(33, 36, 54)",
      "toolbar_text": "rgb(178, 178, 186)",
      "frame": "rgb(11, 12, 27)",
      "tab_background_text": "rgb(178, 178, 186)",
      "toolbar_field": "rgb(11, 12, 27)",
      "toolbar_field_text": "rgb(178, 178, 186)",
      "tab_line": "rgba(67, 194, 218, 0)",
      "popup": "rgb(44, 48, 70)",
      "popup_text": "rgb(188, 189, 200)",
      "button_background_active": "rgb(29, 55, 82)",
      "button_background_hover": "rgb(55, 60, 86)",
      "icons": "rgb(3, 161, 236)",
      "ntp_background": "rgb(22, 24, 40)",
      "ntp_text": "rgb(182, 182, 191)",
      "sidebar_border": "rgb(4, 6, 20)",
      "sidebar_text": "rgb(3, 161, 236)",
      "sidebar": "rgb(11, 12, 27)",
      "tab_text": "rgb(3, 161, 236)",
      "toolbar_field_border": "rgb(3, 161, 236)",
      "toolbar_top_separator": "rgba(4, 6, 20, 0)",
      "tab_loading": "rgba(67, 194, 218, 0)"
    }
  }
}