Examine source code of Twitter DIm

{
  "manifest_version": 2,
  "version": "1.2",
  "name": "twitter_dim_1_2_3",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(21, 32, 43)",
      "toolbar_text": "rgb(192, 192, 192)",
      "frame": "rgb(21, 32, 43)",
      "tab_background_text": "rgb(181, 181, 181)",
      "toolbar_field": "rgba(89, 100, 110, 0.21)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(21, 32, 43)",
      "popup": "rgb(33, 53, 69)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(21, 32, 43)",
      "button_background_hover": "rgba(59, 97, 126, 0.57)",
      "frame_inactive": "rgb(21, 32, 43)",
      "icons_attention": "rgb(181, 181, 181)",
      "icons": "rgb(241, 241, 241)",
      "ntp_background": "rgb(21, 32, 43)",
      "ntp_text": "rgb(21, 32, 43)",
      "popup_border": "rgb(21, 32, 43)",
      "popup_highlight_text": "rgba(59, 97, 126, 0.38)",
      "popup_highlight": "rgb(255, 255, 255)",
      "sidebar_border": "rgb(21, 32, 43)",
      "sidebar_highlight_text": "rgb(21, 32, 43)",
      "sidebar_highlight": "rgb(21, 32, 43)",
      "sidebar_text": "rgb(21, 32, 43)",
      "sidebar": "rgb(21, 32, 43)",
      "tab_background_separator": "rgb(39, 60, 81)",
      "tab_loading": "rgb(21, 32, 43)",
      "tab_selected": "rgb(39, 60, 81)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgba(89, 100, 110, 0.29)",
      "toolbar_field_border_focus": "rgba(89, 100, 110, 0.29)",
      "toolbar_field_border": "rgba(89, 100, 110, 0.29)",
      "toolbar_field_focus": "rgba(89, 100, 110, 0.29)",
      "toolbar_field_highlight_text": "rgb(163, 192, 214)",
      "toolbar_field_highlight": "rgb(88, 110, 128)",
      "toolbar_field_separator": "rgba(89, 100, 110, 0.58)",
      "toolbar_field_text_focus": "rgb(224, 224, 224)",
      "toolbar_top_separator": "rgba(89, 100, 110, 0.29)",
      "toolbar_vertical_separator": "rgba(89, 100, 110, 0.29)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{15a165a6-c9e2-4842-a71d-5ee4d8d3dea1}"
    }
  }
}