Examine source code of Grape Slate

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Grape Slate",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(55, 38, 72, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(46, 21, 53)",
      "tab_background_text": "rgb(199, 199, 199)",
      "toolbar_field": "rgba(83, 49, 80, 0.75)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgba(159, 159, 208, 0)",
      "popup": "rgba(48, 13, 44, 0.95)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(86, 29, 101)",
      "button_background_hover": "rgb(68, 28, 74)",
      "frame_inactive": "rgba(83, 31, 108, 0.75)",
      "icons_attention": "rgb(230, 204, 69)",
      "icons": "rgb(255, 255, 255)",
      "ntp_background": "linear-gradient(-180deg, rgba(116,85,128,1) 0%, rgba(205,20,162,1) 100%)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgba(43, 57, 89, 0)",
      "popup_highlight_text": "rgb(255, 255, 255)",
      "popup_highlight": "rgba(152, 114, 217, 0.2)",
      "tab_background_separator": "rgb(116, 85, 128)",
      "tab_selected": "rgba(129, 99, 136, 0.25)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgba(194, 101, 215, 0.25)",
      "toolbar_field_border_focus": "rgba(83, 31, 108, 0)",
      "toolbar_field_border": "rgba(0, 0, 0, 0)",
      "toolbar_field_focus": "rgb(54, 24, 63)",
      "toolbar_field_highlight_text": "rgb(255, 255, 255)",
      "toolbar_field_highlight": "rgba(96, 44, 98, 0.75)",
      "toolbar_field_separator": "rgb(34, 25, 77)",
      "toolbar_field_text_focus": "rgb(255, 255, 255)",
      "toolbar_top_separator": "rgba(139, 142, 146, 0)",
      "toolbar_vertical_separator": "rgb(116, 85, 128)",
      "tab_loading": "rgba(159, 159, 208, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1763e08f-5c6b-40cf-a459-30f15058ec19}"
    }
  }
}