Examine source code of My Gray Theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "My Gray Theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-009-f069b97f439938a011297c84464f0df6.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(203, 203, 205)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(120, 124, 125)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(250, 250, 251)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgba(255, 255, 255, 0)",
      "popup": "rgb(120, 124, 125)",
      "popup_text": "rgb(255, 255, 255)",
      "icons_attention": "rgb(0, 0, 0)",
      "ntp_background": "rgb(185, 185, 186)",
      "ntp_text": "rgb(72, 72, 72)",
      "popup_highlight": "rgb(120, 124, 125)",
      "sidebar_border": "rgb(203, 203, 205)",
      "sidebar_text": "rgb(255, 255, 255)",
      "sidebar": "rgb(120, 124, 125)",
      "tab_loading": "rgb(255, 255, 255)",
      "tab_selected": "rgb(250, 250, 251)",
      "toolbar_bottom_separator": "rgb(152, 152, 154)",
      "toolbar_field_border": "rgb(185, 185, 186)",
      "toolbar_field_focus": "rgb(250, 250, 251)",
      "toolbar_field_highlight_text": "rgb(255, 255, 255)",
      "toolbar_field_separator": "rgba(255, 255, 255, 0)",
      "toolbar_top_separator": "rgb(152, 152, 154)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3a758b25-2715-46d4-9e14-4be226add271}"
    }
  }
}