Examine source code of Cheeseface

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Cheeseface",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(33, 33, 33)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(212, 228, 30)",
      "tab_background_text": "rgb(33, 33, 33)",
      "toolbar_field": "rgb(23, 23, 23)",
      "toolbar_field_text": "rgb(41, 154, 237)",
      "tab_line": "rgba(6, 93, 159, 0.9)",
      "popup": "rgba(40, 40, 40, 0.95)",
      "popup_text": "rgb(215, 226, 239)",
      "button_background_active": "rgba(212, 228, 30, 0.9)",
      "button_background_hover": "rgba(46, 141, 213, 0.29)",
      "frame_inactive": "rgb(23, 23, 23)",
      "icons_attention": "rgb(28, 165, 65)",
      "ntp_background": "rgb(23, 23, 23)",
      "popup_border": "rgba(25, 25, 25, 0.9)",
      "popup_highlight_text": "rgba(46, 141, 213, 0.9)",
      "popup_highlight": "rgba(212, 228, 30, 0.9)",
      "sidebar_border": "rgb(25, 25, 25)",
      "sidebar_highlight_text": "rgb(212, 228, 30)",
      "sidebar_highlight": "rgba(212, 228, 30, 0.9)",
      "tab_loading": "rgb(28, 165, 65)",
      "tab_selected": "rgb(40, 40, 40)",
      "toolbar_bottom_separator": "rgb(25, 25, 25)",
      "toolbar_field_border": "rgba(40, 40, 40, 0.95)",
      "toolbar_field_focus": "rgb(40, 40, 40)",
      "toolbar_field_highlight_text": "rgba(255, 255, 255, 0.57)",
      "toolbar_field_highlight": "rgba(28, 165, 65, 0.57)",
      "toolbar_field_text_focus": "rgba(11, 130, 220, 0.9)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6656cef2-6fdd-41e5-964a-88723da15f2b}"
    }
  }
}