Examine source code of Modern Steam

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Modern Steam",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(42, 46, 54)",
      "toolbar_text": "rgb(185, 188, 191)",
      "frame": "rgb(24, 29, 36)",
      "tab_background_text": "rgb(185, 188, 191)",
      "toolbar_field": "rgb(42, 46, 54)",
      "toolbar_field_text": "rgb(185, 188, 191)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgb(62, 68, 79)",
      "popup_text": "rgb(220, 222, 223)",
      "button_background_active": "rgb(26, 159, 255)",
      "button_background_hover": "rgb(61, 67, 78)",
      "ntp_background": "rgb(32, 38, 48)",
      "ntp_text": "rgb(185, 188, 191)",
      "popup_border": "rgb(56, 56, 56)",
      "sidebar_border": "rgb(42, 46, 54)",
      "sidebar_highlight_text": "rgb(255, 255, 255)",
      "sidebar_highlight": "rgb(62, 68, 79)",
      "sidebar_text": "rgb(185, 188, 191)",
      "sidebar": "rgb(42, 46, 54)",
      "tab_selected": "rgb(26, 159, 255)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgb(42, 46, 54)",
      "toolbar_field_border": "rgb(42, 46, 54)",
      "toolbar_top_separator": "rgb(24, 29, 36)",
      "tab_loading": "rgb(0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1a2630d1-4861-4f45-8bad-1d00d615ec51}"
    }
  }
}